Covalent organic frameworks (COFs) are revolutionizing the solid-state ionics by programming backbone, incorporating functional groups, and chelating with specific ions in structural units to facilitate rapid ion transport. More encouragingly, topology diagrams enable COFs with tremendous possibilities in structural design from two-dimensional (2D) to three-dimensional (3D) polygonal network, thus positioning themselves as promising ionic solid-state electrolytes for energy storage and conversion. This review summarizes recent advances in COF electrolytes from 2D to 3D, focusing on how pore topology, framework functionality, and composite designs regulate Li⁺ conduction. Mechanistic insights including anion immobilization, backbone–ion interactions, and solvent- or polymer-assisted transport are discussed to elucidate the structure–transport correlations that govern ionic conductivity and interfacial behavior. Key limitations, such as modest intrinsic conductivity, electrode interfacial resistance, and mechanical fragility, are critically examined. Beyond lithium systems, the broader potential of COFs as versatile solid-state ionic conductors for emerging metal-ion batteries is highlighted. Finally, future opportunities are outlined, including ionic-backbone engineering, nanochannel ordering, quasi-solid architectures, dendrite-regulating interfaces, and scalable membrane processing. We earnestly expect that this review will further elucidate pathways for the advancement of COF-based electrolytes toward practical and high-performance solid-state rechargeable batteries.

Addressing the challenges of uranium extraction from seawater (UES) requires innovative strategies to overcome ultralow concentration (3.3 ppb) and thermodynamic limits. Herein, we propose a regioisomeric engineering strategy to design vinylene-linked covalent organic frameworks (COFs) for synergistic adsorption-photocatalytic UES. Two isomeric COFs, β-PTTN-AO and α-PNNB-AO, were synthesized by tuning the substitution positions of amidoxime (AO) groups on olefin bonds. The β-PTTN-AO isomer achieves a remarkable UES capacity of 12.74 ± 0.21 mg·g⁻¹ in nature seawater, surpassing its α-positioned counterpart (8.9 ± 0.18 mg·g⁻¹) and outperforming most reported photocatalysts. Combined experiments and density functional theory (DFT) theoretical studies correlate regioisomeric configurations with electronic structure modulation and photocatalytic activity. Specifically, β-PTTN-AO enhance π-electron delocalization and strengthen built-in electric fields, promoting exciton dissociation, charge separation, and uranium reduction. This work establishes a molecular design paradigm for COF photocatalysts, advancing sustainable nuclear energy through structural isomerism.

Although promising strategies have been developed to resolve the critical drawbacks of lithium-sulfur (Li-S) batteries, the intractable issues including undesirable shuttling of polysulfides and sluggish redox reaction kinetics have still been unresolved thoroughly. Herein, a cobalt single-atom (CoSA) catalyst comprising of atomic Co distributed homogeneously within nitrogen (N)-doped porous carbon (Co-NPC) nanosphere is constructed and utilized as a separator coating in Li-S batteries. The Co-NPC exposes abundant active sites participating in sulfur redox reactions, and remarkable catalytic activity boosting the rapid polysulfide conversions. As a result, Li-S batteries with Co-NPC coating layer realize significantly enhanced specific capacity (1295 mAh·g⁻¹ at 0.2 C), rate capability (753 mAh·g⁻¹ at 3.0 C), and long-life cyclic stability (601 mAh·g⁻¹ after 500 cycles at 1.0 C). Increasing the areal sulfur loading to 6.2 mg·cm⁻², an extremely high areal capacity of 7.92 mAh·cm⁻² is achieved. Further in situ X-ray diffraction, density functional theory calculations, and secondary ion mass spectrometry confirm the high catalytic capability of CoSA towards reversible polysulfide conversion. This study supplies new insights for adopting single-atom catalyst to upgrade the electrochemical performance of Li-S batteries.