Macrocycle-Based Solid-State Lithium Electrolytes: Supramolecular Strategies and Ion-Transport Regulation
The rapid demand for high-energy-density lithium batteries necessitates advanced solid-state electrolytes (SSEs) to overcome the safety and performance limitations of conventional liquid counterparts. Macrocyclic compounds, with their well-defined cavities, programmable binding sites, and tunable self-assembly, have emerged as powerful molecular regulators for designing next-generation SSEs. This review examines recent advancements in macrocyclic compound-based SSEs by categorizing their functions into four fundamental supramolecular regulation paradigms: cation-centered regulation (e.g., crown ethers), anion-centered regulation (e.g., calixarenes and calixpyrroles), channel-dominated transport (e.g., cyclodextrins), and hybrid regulation (e.g., cucurbiturils). We elucidate how these macrocycles precisely control ion coordination, modulate migration dynamics, and reshape interfacial chemistry, leading to enhanced ionic conductivity, improved Li+ transference numbers, suppressed lithium dendrite growth, and superior interfacial stability. While each paradigm offers distinct advantages, the most promising SSEs often leverage synergistic combinations of these strategies. Finally, we highlight the remaining challenges, including synthetic complexity and multi-objective performance trade-offs, and propose future research directions for developing highly efficient and durable macrocycle-based solid-state lithium batteries.