Shi Ruijuan, Liu Luojia, Lu Yong, Wang Chenchen, Li Yixin, Li Lin, Yan Zhenhua, Chen Jun
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Tianjin, 300071, China.
Nat Commun. 2020 Jan 10;11(1):178. doi: 10.1038/s41467-019-13739-5.
Covalent organic frameworks with designable periodic skeletons and ordered nanopores have attracted increasing attention as promising cathode materials for rechargeable batteries. However, the reported cathodes are plagued by limited capacity and unsatisfying rate performance. Here we report a honeycomb-like nitrogen-rich covalent organic framework with multiple carbonyls. The sodium storage ability of pyrazines and carbonyls and the up-to twelve sodium-ion redox chemistry mechanism for each repetitive unit have been demonstrated by in/ex-situ Fourier transform infrared spectra and density functional theory calculations. The insoluble electrode exhibits a remarkably high specific capacity of 452.0 mAh g, excellent cycling stability (~96% capacity retention after 1000 cycles) and high rate performance (134.3 mAh g at 10.0 A g). Furthermore, a pouch-type battery is assembled, displaying the gravimetric and volumetric energy density of 101.1 Wh kg and 78.5 Wh L, respectively, indicating potentially practical applications of conjugated polymers in rechargeable batteries.
具有可设计的周期性骨架和有序纳米孔的共价有机框架作为可充电电池有前景的阴极材料受到了越来越多的关注。然而，报道的阴极存在容量有限和倍率性能不尽人意的问题。在此，我们报道了一种具有多个羰基的蜂窝状富氮共价有机框架。通过原位/非原位傅里叶变换红外光谱和密度泛函理论计算，证明了吡嗪和羰基的储钠能力以及每个重复单元高达十二的钠离子氧化还原化学机理。该不溶性电极表现出452.0 mAh g的极高比容量、优异的循环稳定性（1000次循环后容量保持率约96%）和高倍率性能（10.0 A g时为134.3 mAh g）。此外，组装了软包电池，其重量能量密度和体积能量密度分别为101.1 Wh kg和78.5 Wh L，表明共轭聚合物在可充电电池中具有潜在的实际应用。
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