Nitrogen-Doped\nGraphene-Supported Tungsten Oxynitride\nNanoparticles as an Efficient Bidirectional Polysulfide Convertor\nfor Advanced Lithium–Sulfur Batteries

Catalytic\nmaterials are considered pivotal in addressing the sluggish\nkinetics and shuttle effect in lithium–sulfur batteries (LSBs).\nHowever, effectively harnessing the utilization rate of active sites\nwithin catalytic materials remains a pivotal challenge. In this study,\na novel conductive nitrogen-doped graphene-loaded tungsten oxynitride\nnanoparticle (WNO/NG) with abundant active sites is prepared through\na polymer-assisted templating method for serving as a sulfur host.\nElectrochemical analysis coupled with <i>in situ</i> XRD\nconfirm the dual-directional electrocatalytic behavior of WNO/NG for\naccelerating the conversion of lithium polysulfide (LiPSs). Theoretical\ncalculations demonstrate that the intrinsic mechanism underlying the\nperformance enhancement is attributed to the high inherent conductivity\nof WNO/NG and the efficient interface charge transfer with LiPSs.\nThe assembled 500 mAh pouch cell delivers a 97% capacity retention\nafter 25 cycles. This strategy provides valuable insights for designing\ncatalytic materials with abundant activity sites and sheds light on\nthe mechanisms of catalytic enhancement in Li–S chemistry.