Covalent organic framework (COF) materials with porous character and robust structure have significant applied implications for Kion 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 −1 at 0.1 C), rate capability (185 mAh g −1 at 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.

Due to the large size and heavy mass of K-ion, the pursuit of reliable anodes with outstanding comprehensive performance for K-ion batteries (KIBs) remains a formidable challenge. Typically, high-capacity potassium...

No abstract

Developing effective catalysts to degrade chemical warfare agents is of great significance. Herein, a mesoporous MIL‐101(Cr) composite material dangled with porphyrin molecules (denote as TCPP@MIL‐101(Cr), TCPP = tetra(4‐carboxyphenyl)porphyrin) is reported, which can be used as a heterogeneous photocatalyst for detoxification of mustard gas simulants 2‐chloroethyl ethyl sulfide (CEES) to 2‐chloroethyl ethyl sulfoxide (CEESO) with a half‐life of 1 min. The catalytic performance of TCPP@MIL‐101(Cr) is comparable to that of homogeneous molecular porphyrin. Mechanistic studies reveal that both 1O2 and O2•− are efficiently generated and play vital roles in the oxidation reaction. Gold nanoparticles (AuNPs) are attached to the TCPP@MIL‐101(Cr) to further enhance the catalytic activity with a benchmark half‐life of 45 s, which is the fastest record so far. A medical mask loaded TCPP@MIL‐101(Cr) is fabricated for practical applications, which can selectively photoxidize CEES to CEESO under sunlight and air atmosphere, exhibiting the best degradation performance among the reported fabric‐like composite materials.

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–1 at 0.1C), superb rate capability (151 and 95 mAh g–1 at 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.