High‐Capacity Lithium‐Sulfur Battery Cathode: Sulfurized Polyacrylonitrile Aerogel Based on Regulation of Aggregated Structure

Sulfurized polyacrylonitrile is considered one of the most promising cathode materials for lithium‐sulfur batteries due to its high electronic conductivity, minimal polysulfide shuttling, high reversible specific capacity, and excellent cycling stability. However, its practical application is hindered by volume expansion during battery operation. To address this issue, a sulfurized polyacrylonitrile cathode with a porous framework is designed via solvent/non‐solvent exchange regulation, where by using high‐pressure spray‐assisted phase separation, an amorphous‐dominated 3D interpenetrating aerogel is constructed. This architecture facilitates continuous and rapid charge transfer as well as efficient electrolyte infiltration, and the porous skeleton helps accommodate volume changes during charge‐discharge cycles. As a result, the sulfurized polyacrylonitrile aerogel cathode achieves a capacity retention of over 92.3% after 700 cycles at 0.5 C and delivers an initial energy density of 790.8 Wh kg − 1 at 0.2 C. In a full‐cell configuration with a prelithiated graphite anode, a reversible capacity as high as 1014 mAh g − 1 with greater than 94.8% capacity retention is maintained after 180 cycles at 0.2 C. This work highlights the importance of rational electrode microstructure engineering and provides an effective strategy for developing high‐performance sulfurized polyacrylonitrile cathodes in lithium‐sulfur batteries.