Rare‐Earth Doped Configurational Entropy Stabilized High Entropy Spinel Oxide as an Efficient Anchoring/Catalyst Functional Interlayer for High‐Performance Lithium‐Sulfur Battery

Abstract Lithium‐sulfur batteries (LSBs) are one of the most promising and potential modern‐day energy storage devices due to the low‐cost sulfur‐based cathode and remarkably high energy density (∼2600 Wh kg −1 ). However, the detrimental shuttle effect of lithium polysulfide (LiPS) and the sluggish electrochemical redox kinetics of lithium sulfide (Li 2 S) formation restrict its commercial viability. Herein, we design a novel transition metal‐rare earth high entropy oxide (TM‐RE HEO) Co 0.08 Mn 0.08 Ni 0.08 Fe 1.96 Mg 0.08 Nd 0.01 Gd 0.01 Sm 0.01 Pr 0.01 O 4 as a polysulfide adsorbent and catalyst for the redox reactions of sulfur species in Li−S battery. TM‐RE HEO interlayer exhibits an excellent discharge capacity of 1146 mAh g −1 at 0.1 C rate, high rate capability, and reasonable long‐term cycling stability at 0.5 C rate with a low capacity decay of 0.08 % per cycle after 300 cycles. High degree of chemical confinement of soluble polysulfides, as demonstrated by the strong bonding between TM‐RE HEO and Li 2 S 6 , and expedited catalytic conversion to insoluble Li 2 S, result from strong polar catalytically active multiple metal sites and abundant oxygen vacancies. This work demonstrates the potential of high entropy oxide in developing high‐efficiency LSB technology.