Electrospun Sulfurized Polyacrylonitrile Nanofibers for Long-Term Cycling Stability and High-Rate Lithium–Sulfur Batteries

As a promising cathode material for lithium–sulfur (Li-S) batteries, sulfurized polyacrylonitrile (SPAN) with uniform dispersion of short-chain sulfur moieties on its organic skeletons can effectively avoid lithium polysulfides dissolution and exhibit high specific capacity and long-term cycling stability. However, the practical battery performance of the SPAN cathode is dramatically limited by its relatively poor ionic and electronic accessibility. In this work, a three-dimensional (3D) network of Se0.05S0.95PAN nanofibers incorporated with commercial and low-cost Ketjen black (KB), denoted as ES-KBS@Se0.05S0.95PAN, is prepared through the electrospinning method. This unique 3D nanofiber structure is beneficial to transport lithium ions and electrons and accommodate volume expansion during lithiation/delithiation processes for Li-S batteries, leading to tremendous improvement of sulfur utilization, rate capability, and long-term cycling performance. ES-KBS@Se0.05S0.95PAN exhibits an ultrahigh reversible capacity of 1491 mAh g–1 at 0.1C and 1130 mAh g–1 at 5C and retains 1224 mAh g–1 after 500 cycles at 1C, corresponding to a capacity retention of 96.4%. This work proposes a facile strategy for the preparation of sulfur cathodes applicable in lithium–sulfur batteries.