Covalent organic frameworks: a new platform for next-generation batteries of Na-, K- and Zn-ions

Review on Cooperative Catalysis for Room-Temperature Sodium-Sulfur Batteries

The low cost and high energy density characteristics of room-temperature sodium-sulfur (RT Na-S) batteries remarkably promote the development of sustainable large-scale energy-storage systems. However, there are serious problems with the shuttle effect and slow conversion kinetics caused by polysulfide dissolution in RT Na-S batteries, which can lead to decreased coulombic efficiency, rapid capacity degradation, and poor rate performance, hindering the practical application of RT Na-S batteries. Recently, numerous multimodal approaches have been attempted to address these issues, thereby promoting cycling stability and raising the energy density of RT Na-S batteries to a higher level. However, there is still a lack of a comprehensive and systematic summary of catalyst design based on the cooperative catalysis principle. In this review, the application advantages, operation mechanisms, and main challenges of RT Na-S batteries are first introduced. After that, the latest progress based on cooperative catalysts is elaborately summarized, exploring the corresponding work mechanisms and design principles of RT Na-S batteries. Finally, a summary of future research directions for developing high-performance RT Na-S batteries is presented.

Synergistic Linker and Linkage of Covalent Organic Frameworks for Enhancing Gold Capture

The tunable pore walls and skeletons render covalent organic frameworks (COFs) as promising absorbents for gold (Au) ion. However, most of these COFs suffered from low surface areas hindering binding sites exposed and weak binding interaction resulting in sluggish kinetic performance. In this study, COFs have been constructed with synergistic linker and linkage for high-efficiency Au capture. The designed COFs (PYTA-PZDH-COF and PYTA-BPDH-COF) with pyrazine or bipyridine as linkers showed high surface areas of 1692 and 2076 m2 g‒1, providing high exposed surface areas for Au capture. In addition, the Lewis basic nitrogen atoms from the linkers and linkages are easily hydronium, which enabled to fast trap Au via coulomb force. The PYTA-PZDH-COF and PYTA-BPDH-COF showed maximum Au capture capacities of 2314 and 1810 mg g-1, higher than other reported COFs. More importantly, PYTA-PZDH-COF are capable of rapid adsorption kinetics with achieving 95% of maximum binding capacity in 10 min. The theoretical calculation revealed that the nitrogen atoms in linkers and linkages from both COFs are simultaneously hydronium, and then the protonated PYTA-PZDH-COF are more easily binding the AuCl4 ‒, further accelerating the binding process. This study gives the a new insight to design COFs for ion capture.

Porous crystalline conjugated macrocyclic materials and their energy storage applications

Porous crystalline conjugated macrocyclic materials (CMMs) possess high porosity, tunable structure/function and efficient charge transport ability owing to their planar macrocyclic conjugated π-electron system, which make them promising candidates for applications in energy storage. In this review, we thoroughly summarize the timely development of porous crystalline CMMs in energy storage related fields. Specifically, we summarize and discuss their structures and properties. In addition, their energy storage applications, such as lithium ion batteries, lithium sulfur batteries, sodium ion batteries, potassium ion batteries, Li-CO2 batteries, Li-O2 batteries, Zn-air batteries, supercapacitors and triboelectric nanogenerators, are also discussed. Finally, we present the existing challenges and future prospects. We hope this review will inspire the development of advanced energy storage materials based on porous crystalline CMMs.

A Nitro-Rich Small-Molecule-Based Organic Cathode Material for Effective Rechargeable Lithium Batteries

Organic cathode materials have attracted extensive research interest for rechargeable lithium-ion batteries (LIBs) because of their diverse structures and tunable properties. However, the preparation of organic cathode materials with high capacities, long cycling life, and high energy densities still remains a big challenge. To address these issues, we designed and synthesized a novel multinitro-decorated organic small molecule, N⁴,N^4''-bis(2,4-dinitrophenyl)-5'-(4-((2,4-dinitrophenyl)amino)phenyl)-[1,1':3',1''-terphenyl]-4,4''-diamine (TAPB-6NO₂), where the unique electronic character of nitro group should enable TAPB-6NO₂ to be a promising cathode candidate for LIBs. We found that the introduction of multiple nitro groups could efficiently reduce the solubility of TAPB-6NO₂ in organic electrolytes, resulting in a high specific capacity of around 180 mAh g^-1 and stable cycling with a capacity retention of 91% after 1100 cycles at 1000 mA g^-1. This work suggests that attaching multiple nitro groups on a small molecule is an effective approach to construct high-performance organic cathode materials for stable and sustainable rechargeable LIBs.