Scalable Synthesis of Ultrathin Polyimide Covalent Organic Framework Nanosheets for High-Performance Lithium–Sulfur Batteries

作者：Haiyan Duan, Ke Li, Mo Xie, Jiaming Chen, Hou-Gan Zhou, Xiaofeng Wu, Guo‐Hong Ning, Andrew I. Cooper, Dan Li · 发表于：Journal of the American Chemical Society · 年份：2021 · DOI：10.1021/jacs.1c08675 · 被引用次数：267 · 研究领域：Covalent Organic Framework Applications、Advanced Battery Materials and Technologies、Polyoxometalates: Synthesis and Applications

Development of new porous materials as hosts to suppress the dissolution and shuttle of lithium polysulfides is beneficial for constructing highly efficient lithium–sulfur batteries (LSBs). Although 2D covalent organic frameworks (COFs) as host materials exhibit promising potential for LSBs, their performance is still not satisfactory. Herein, we develop polyimide COFs (PI-COF) with a well-defined lamellar structure, which can be exfoliated into ultrathin (∼1.2 nm) 2D polyimide nanosheets (PI-CONs) with a large size (∼6 μm) and large quantity (40 mg/batch). Explored as new sulfur host materials for LSBs, PI-COF and PI-CONs deliver high capacities (1330 and 1205 mA h g –1 at 0.1 C, respectively), excellent rate capabilities (620 and 503 mA h g –1 at 4 C, respectively), and superior cycling stability (96% capacity retention at 0.2 C for PI-CONs) by virtue of the synergy of robust conjugated porous frameworks and strong oxygen–lithium interactions, surpassing the vast majority of organic/polymeric lithium–sulfur battery cathodes ever reported. Our finding demonstrates that ultrathin 2D COF nanosheets with carbonyl groups could be promising host materials for LSBs with excellent electrochemical performance.