Vanadium Nitride Nanowires Array on Carbon Nanofiber Paper for Regulating Polysulfides Toward Stable Freestanding Sulfur Cathode

Abstract

The construction of the freestanding cathodes with high sulfur loading is one of the key approaches to achieve high-energy-density lithium–sulfur (Li–S) batteries. However, these freestanding sulfur cathodes often face challenges including low sulfur utilization, poor rate capability, and low cycling stability. Herein, a highly conductive freestanding sulfur cathode based on carbon fiber paper (CFP) and vanadium nitride (VN) nanowires array is reported. The uniformly distributed VN nanowires on CFP can effectively interact with sulfur species akin to ropes, which not only suppresses the polysulfides shuttling effect but also facilitates catalytic conversion of polysulfides. Additionally, the closely adhered VN nanowires on CFP support Li⁺ transport without hindrance, leveraging their high conductivity to promote redox kinetics. Therefore, the freestanding sulfur cathodes exhibit stable cycling performance even under high sulfur loading of 7.0 mg cm⁻², a high areal capacity of 7.8 mA h cm⁻² is achieved. This work provides valuable approaches to the assembly of freestanding sulfur electrodes for high-energy-density and long-lifetime Li–S batteries.