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

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 (similar to 2600 Wh kg(-1)). However, the detrimental shuttle effect of lithium polysulfide (LiPS) and the sluggish electrochemical redox kinetics of lithium sulfide (Li2S) formation restrict its commercial viability. Herein, we design a novel transition metal-rare earth high entropy oxide (TM-RE HEO) Co0.08Mn0.08Ni0.08Fe1.96Mg0.08Nd0.01Gd0.01Sm0.01Pr0.01O4 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 Li2S6, and expedited catalytic conversion to insoluble Li2S, 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.

Automated summary

Lithium-sulfur batteries (LSBs) are promising energy storage devices due to low-cost sulfur-based cathode and high energy density. However, the shuttle effect of lithium polysulfide (LiPS) and slow redox kinetics of lithium sulfide (Li2S) formation hinder their commercial viability. In this study, a transition metal-rare earth high entropy oxide (TM-RE HEO) was designed as a polysulfide adsorbent and catalyst for redox reactions in Li-S batteries. The TM-RE HEO demonstrated enhanced discharge capacity, high rate capability, and long-term cycling stability. This work highlights the potential of high entropy oxide in developing efficient LSB technology.