No abstract

Aqueous zinc (Zn) ion batteries with low cost and high safety are promising devices for grid energy storage; however, the Zn anode problems, including dendrite growth and parasitic side reactions, severely retard their practical implementation. Here, a two-dimensional covalentorganic framework (COF) coating is developed to address these issues. Under the regulation of an optimal modulator, the prepared COF (COF− H) containing rich alkynyl units in an AA-stacking mode not only features a flower-like structure but also exhibits high crystallinity, large surface area, and high stability in strong acid and base medium. Consequently, the Zn anode with this COF-based artificial interface layer greatly mitigates the surface corrosion and efficiently suppresses the growth of the Zn dendrite, which is mainly attributed to the homogeneous distribution of Zn 2+ in uniform channels and strong affinity of electron-rich sites including alkynyl, ketone, and enamine groups in COF−H toward Zn 2+ . The resulting Zn anode endows the symmetric cell with a long cycling lifetime of over 900 h at 3 mA cm −2 and promotes the cyclability of the COF@ Zn||MnO 2 full cell. This study provides insights into designing highly crystalline COFs and constructing a highly reversible Zn anode for advanced rechargeable aqueous Zn ion batteries.

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Lithium–sulfur (Li–S) batteries hold great promise for new-generation energy storage technologies owing to their overwhelming energy density. However, the poor conductivity of active sulfur and the shuttle effect limit their widespread use. Herein, a carbon cloth decorated with thiol-containing UiO-66 nanoparticles (CC@UiO-66­(SH)2) was developed to substitute the traditional interlayer and current collector for Li–S batteries. One side of CC@UiO-66­(SH)2 acts as a current collector to load active materials, while the other side serves as an interlayer to further restrain polysulfide shuttling. This two-in-one integrated architecture endows the sulfur cathode with fast electron/ion transport and efficient chemical confinement of polysulfides. More importantly, rich thiol groups in the pores of UiO-66­(SH)2 serve to tether polysulfides by both covalent interactions and lithium bonding. Therefore, the Li–S battery equipped with this integrated interlayer–current collector not only delivers an enhanced specific capability (1209 mAh g–1 at 0.1 C) but also exhibits prominent cycling stability (an attenuation rate of 0.037% per cycle for 1000 cycles at 1 C). Meanwhile, the battery achieves a high discharge capacity of 795 mAh g–1 at a sulfur loading of 3.83 mg cm–2. The new metal–organic framework (MOF)-based electrode material reported in this study undoubtedly provides insights into the exploration of functional MOFs for robust Li–S batteries.

Conjugated microporous polymers (CMPs) with porous structure and rich polar units are favorable for high-performance lithium−sulfur (Li−S) batteries. However, understanding the role of building blocks in polysulfide catalytic conversion is still limited. In this work, two triazine-based CMPs are constructed by electron-accepting triazine with electron-donating triphenylbenzene (CMP-B) or electron-accepting triphenyltriazine (CMP-T), which can grow on a conductive carbon nanotube (CNT) to serve as separator modifiers for Li−S batteries.