Structural Motifs for Modeling Sulfur‐Poly(acrylonitrile) Composite Materials in Sulfur‐Lithium Batteries

Key structural motifs of cyclized‐poly(acrylonitrile) (PAN) and sulfur/PAN composite (SPAN) are identified and their energies are evaluated using density functional theory (DFT). Energetically favorable structural motifs are utilized to design smaller representative molecular models of both PAN and SPAN for in‐depth investigations. A zig‐zag configuration with multiple kink sites is energetically favorable for PAN materials, with the carbon kink site being the most reactive site. To form SPAN, sulfur binds to this kink site, resulting in structures typically containing S=C double bonds at kink sites and S chains that bridge between neighboring PAN fragments. It is found that the formation of large sulfur rings is possible because they are flexible enough to accommodate their length to the shape of the PAN fragment. Zig‐zag patterns: Key structural motifs of cyclized‐poly(acrylonitrile) (PAN) and sulfur/PAN composite (SPAN) are identified and their energies are evaluated using density functional theory (DFT). A zig‐zag configuration with multiple kink sites is energetically favorable for PAN materials. The most stable SPAN configurations typically contain S=C double bonds at kink and edge sites and sulfur chains that bridge between neighboring backbones.