The diffusion and loss of lithium polysulfides (LiPSs) in lithium-sulfur batteries (LSBs) reduce the sulfur utilization rate and the catalytic conversion efficiency of sulfur species, resulting in early battery failure. Li₂ZnTi₃O₈ (LZTO), characterized by its stable spinel structure, exhibits high Li⁺ conductivity and holds great potential as an effective adsorbent for LiPSs. This study proposes a collaborative design concept of LZTO host–separator modifier, which offers a complementary and matching approach in the cathode side, effectively addressing the challenges associated with dissolution and inadequate conversion of LiPSs. Density functional theory (DFT) calculation substantiates the pronounced chemical affinity of LZTO towards LiPSs. More importantly, the high efficiency ion transport channels are achieved in separator coating due to the presence of the LZTO particles. Furthermore, the catalytic efficacy of LZTO is validated through meticulous analysis of symmetric batteries and Tafel curves. Consequently, the LZTO host–separator modifier-based cell displays satisfactory rate capability (1449 and 1166 mAh·g⁻¹ at 0.1 and 0.5 C) and an impressively capacity (606 mAh·g⁻¹ after 500 cycles at 1 C). The coordinated strategy of host–separator modifier is supposed to have wide applications in LSBs.

Solid-state electrolytes have attracted considerable attention in new energy-related devices due to their high safety and broad application platform. Polyoxometalates (POMs) are a kind of molecular-level cluster compounds with unique structures. In recent years, owing to their abundant physicochemical properties (including high ionic conductivity and reversible redox activity), POMs have shown great potential in becoming a new generation of solid-state electrolytes. In this review, an overview is investigated about how POMs have evolved as ion-conducting materials from basic research to novel solid-state electrolytes in energy devices. First, some expressive POM-based ion-conducting materials in recent years are introduced and classified, mainly inspecting their structural and functional relationship. After that, it is further focused on the application of these ion-conducting electrolytes in the fields of proton exchange membranes, supercapacitors, and ion batteries. In addition, some properties of POMs (such as inherent dimension, capable of forming stable hydrogen bonds, and reversible bonding to water molecules) enable these functional POM-based electrolytes to be employed in innovative applications such as ion selection, humidity sensing, and smart materials. Finally, some fundamental recommendations are given on the current opportunities and challenges of POM-based ion-conducting electrolytes.