Harnessing medium entropy and oxygen defects in spinel ferrite cathodes for enhanced cycling performance in lithium–sulfur batteries

Abstract

The unique structure of medium entropy materials has garnered significant attention in the field of batteries. Medium-entropy spinel ferrite, as a new cathode material for lithium–sulfur batteries, presents boundless possibilities to tailor charge–discharge performance. Herein, abundant oxygen vacancies were implanted into medium-entropy spinel ferrites and utilized as cathode materials for lithium–sulfur batteries to address the challenges associated with the sluggish shuttle and conversion kinetics of lithium polysulfides (LiPSs) during charge–discharge processes in Li–S batteries. The synergistic effects among multiple species highlight the advantages of medium entropy features. The presence of oxygen vacancies mitigates the energy barrier associated with the decomposition reaction, thereby facilitating charge transfer kinetics and promoting LiPSs conversion. Oxygen vacancies can be readily implanted into the medium-entropy spinel ferrite, thereby enabling the distinctive medium-entropy-driven influence of oxygen vacancies on the favorable rate capability and prolonged cycling performance of lithium–sulfur batteries. This study presents a promising approach for utilizing design defects in medium-entropy ferrites within the realm of battery applications.