Progress and Opportunities of Vanadium-Based Compounds as Cathode Hosts, Decoration Layers of Separators, and Interlayers in Lithium Sulfur Batteries

Vanadium (V)-based compounds are increasingly used in lithium sulfur batteries because of their great working potential, large polarities, easily designed hierarchical structures, and moderate combination of V with nonmetallic atoms. In this review, recent advances regarding vanadium oxides, vanadium sulfides, vanadium nitrogens, and coupling systems of vanadium oxide/nitrogen/carbide as cathode hosts, decoration layers of separators, and interlayers are systematically introduced. Especially, the electrochemical enhancement mechanisms of the V-based compound hosts on the inhibition of the shuttle effect mainly include physical confinement, chemical anchoring, and catalytic conversion. The chemical interactions between VOx/VSx/VN hosts and LiPSs are Li-O or V-S, V-S, and Li-N or V-S bonds, respectively, and VSx has more modest sulfiphilic properties to sulfur-containing species than VOx. Besides, strategies for increasing effective areal S loading are refined as designing the hierarchical structure and selecting a suitable loading method. We hope that this review will shed light on the importance of V-based composites in lithium sulfur batteries and promote the further development of lithium sulfur batteries.