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Covalent organic framework (COF) materials with porous character and robust structure have significant applied implications for K-ion battery (KIB) anodes, but they are limited by the low reversible capacity and inferior rate capability. Here, based on theoretical calculations, we identified that a porous bulk COF featuring numerous pyrazines and carbonyls in the π-conjugated periodic skeleton could provide multiple accessible redox-active sites for high-performance potassium storage. Its porous structure with a surface-dominated storage mechanism enabled the fast and stable storage of K-ions. Its insolubility in organic electrolytes and small volumetric change after potassiation ensured a robust electrode for stable cycling. As a KIB anode, this bulk COF demonstrated an unprecedentedly outstanding combination of reversible capacity (423 mAh g–1at 0.1 C), rate capability (185 mAh g–1at 10 C), and cyclability. The theoretical simulation and comprehensive characterizations confirmed the active sites are contributed by C═O, C═N, and the cation−π effect.

Charged metal-organic cages generally produce aggregates with various morphologies and different properties through the multiple supramolecular interactions in solution. Herein, a luminescent hexahedral metal-organic cage containing pyrene chromophores is successfully constructed through coordination-driven subcomponent self-assembly. The cage exhibits novel spontaneous aggregation in a dilute solution and time-dependent luminescence enhancement behavior during the subsequent incubation process. Dynamic light scatter (DLS) and transmission electron microscopy (TEM) results prove that the metal-organic cages can form blackberry-like aggregates in methanol dilute solution. Unexpectedly, the luminescent intensity of this system shows a linear increase with the extension of the incubation time in methanol, and this process is also reflected in the change in the quantum yield of the system (2% to over 80% after 5 days incubation time). Ultraviolet-visible (UV-vis), 1H nuclear magnetic resonance (1H NMR) and mass spectra show that metal-organic cages can stably exist in dilute solution. Time-depended DLS and TEM data reveal that the aggregates of metal-organic cages are gradually changed from the dense state to the loose one, which may involve the transition of the system from an energy unstable state to a stable one, probably leading to the unusual time-dependent luminescent property. This unique time-dependent luminescent cage aggregate can be potentially applied as a “supramolecular time meter”.

Herein, we report an iron-promoted carbonylation-rearrangement of α-aminoaryl-tethered alkylidene cyclopropanes with CO2to generate quinolinofuran derivatives. A variety of quinolinofuran derivatives are obtained in moderate to excellent yields, and two promising luminescent material molecules have been synthesized using the developed method. The Lewis acid FeCl3was introduced into this reaction, which effectively promoted the ring opening and rearrangement of cyclopropanes. This reaction features a broad substrate scope, satisfactory functional group tolerance, facile scalability, and easy derivatization of the products.

Polymer anodes have inspired considerable research interest for Na-ion batteries (NIBs) owing to their high structural flexibility and resource sustainability but are limited by the sluggish electrode kinetics, insufficient cyclability, and inferior electronic conductivity which usually made a large fraction (20–50 wt %) of conductive carbon additive necessitated. Herein, using a polymeric carbon nitride (PCN) anode as an example, we demonstrated that a moderate pyrolysis of the polymer anode could not only reduce its optical bandgap to enhance its electronic conductivity but also tune its microstructures to facilitate Na+transfer/storage and sustain the repeated sodiation/desodiation. When used as NIBs anode with 10 wt % conductive carbon adding for preparing the electrode film, the moderate-pyrolysis PCN can promise high specific capacity (351 mAh g–1at 0.1C), superb rate capability (151 and 95 mAh g–1at 10C and 20C, respectively), and ultrastable cyclability (88.5% capacity retention after 6500 cycles at 2C). This comprehensive battery performance is much better than that of the previously reported organic counterparts. Our finding opened a new avenue in designing high-performance polymer anode for Na-ion batteries.