High?Entropy Spinel Oxide Nanofibers as Catalytic Sulfur Hosts Promise the High Gravimetric and Volumetric Capacities for Lithium–Sulfur Batteries

The exploration of new catalytic hosts is highly important to tackle the sluggish electrochemical kinetics sulfur redox for achieving high energy density lithium–sulfur batteries. Herein, first time, we present high-entropy oxide (HEO, (Mg0.2Mn0.2Ni0.2Co0.2Zn0.2)Fe2O4) nanofibers as host sulfur. HEO show a synergistic effect among multiple metal cations in spinel structure that enables strong chemical confinement soluble polysulfides and fast polysulfide conversion. Consequently, S/HEO composite displays gravimetric capacity 1368.7 mAh g?1 at 0.1 C rate, excellent rate capability with discharge 632.1 5 desirable cycle stability. Furthermore, shows utilization good stability under harsh operating condition loading (4.6 mg cm?2) or low electrolyte/sulfur ratio (5 ?L mg?1). More impressively, volumetric 2627.9 cm?3 achieved simultaneously due tap 1.92 g cm?3, nearly 2.5 times conventional sulfur/carbon composite. Therefore, based on materials, this work affords fresh concept elevating gravimetric/volumetric capacities cathodes