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Despite great promise as next-generation high-capacity energy storage devices, lithium–sulfur batteries still face technical challenges in long-term cyclability. With their porous structures and facile synthesis, metal–organic frameworks (MOFs) are tunable platforms for understanding polysulfide redox and can serve as effective sulfur hosts for lithium–sulfur batteries. This feature article describes our design strategies to tailor MOF properties such as polysulfide affinity, ionic conductivity, and porosity for promoting active material utilization and charge transport efficiency. We also present engineering approaches for implementing MOF-based sulfur cathodes for lithium–sulfur batteries with high volumetric density and under low temperature operation. Our studies provide fundamental insights into sulfur–host interactions and polysulfide electrochemistry in the presence of porous matrices, inspiring future designs of advanced batteries. 

Abstract Lithium–sulfur batteries are promising candidates for next‐generation energy storage devices due to their outstanding theoretical energy density. However, they suffer from low sulfur utilization and poor cyclability, greatly limiting their practical implementation. Herein, we adopted a phosphate‐functionalized zirconium metal–organic framework (Zr‐MOF) as a sulfur host. With their porous structure, remarkable electrochemical stability, and synthetic versatility, Zr‐MOFs present great potential in preventing soluble polysulfides from leaching. Phosphate groups were introduced to the framework post‐synthetically since they have shown a strong affinity towards lithium polysulfides and an ability to facilitate Li ion transport. The successful incorporation of phosphate in MOF‐808 was demonstrated by a series of techniques including infrared spectroscopy, solid‐state nuclear magnetic resonance spectroscopy, and X‐ray pair distribution function analysis. When employed in batteries, phosphate‐functionalized Zr‐MOF (MOF‐808‐PO4) exhibits significantly enhanced sulfur utilization and ion diffusion compared to the parent framework, leading to higher capacity and rate capability. The improved capacity retention and inhibited self‐discharge rate also demonstrate effective polysulfide encapsulation utilizing MOF‐808‐PO4. Furthermore, we explored their potential towards high‐density batteries by examining the cycling performance at various sulfur loadings. Our approach to correlate structure with function using hybrid inorganic–organic materials offers new chemical design strategies for advancing battery materials.