Tungsten Carbide\nEmbedded in a Porous Carbon Nanofiber\nSandwich Structure Electrode: A Strategy to Improve the Performance\nof Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries hold significant\npromise due to high energy density, cost-effectiveness, and ecological\nsustainability, but their practical applications are constrained by\nsuboptimal electrochemical performance and the detrimental shuttle\neffect. Herein, a porous, sandwich-structured composite was developed\nto function as a freestanding cathode designed for Li–S batteries\nwithout aluminum foil. Porous carbon nanofibers (PCNF) were employed\nas the conductive matrix for sulfur, with tungsten carbide (WC) being\nincorporated to furnish abundant active sites for polysulfide adsorption.\nThe findings indicate that the WC-PCNF<sub><i>x</i></sub> conductive network, formed by tungsten carbide embedded within the\nporous carbon nanofiber sandwich structure, markedly enhances the\nactive material exploitation, improves polysulfide adsorption, and\ndemonstrates superior sulfur loading capacity and cyclic stability.\nConsequently, the synthesized WC-PCNF<sub>2</sub> composite material\nexhibited an outstanding capacity of 872.5 mAh/g under a high sulfur\nloading of 4.0 mg/cm<sup>2</sup> after 200 cycles at 0.2 C, with a\ncommendable capacity retention rate of 85%. The metal carbide-embedded\nporous carbon network cathode material presents a practical approach\nto enhancing sandwich-structured electrodes.