Integrated Covalent Organic Framework/Carbon Nanotube Composite as Li-Ion Positive Electrode with Ultra-High Rate Performance
Integrated Covalent Organic Framework/Carbon Nanotube Composite as Li-Ion Positive Electrode with Ultra-High Rate Performance
复制标题
共价有机框架/碳纳米管一体化复合材料用作具有超高倍率性能的锂离子正极材料
DOI：
10.1002/aenm.202101880
复制
发表时间：
2021-09-12
影响因子：
27.8
通讯作者：
Cooper, Andrew, I
中科院分区：
文献类型：
--
作者：
Gao, Hui;Zhu, Qiang;Cooper, Andrew, I
共价有机骨架材料是一种很有前途的锂离子电池电极材料。然而，嵌在COF内的氧化还原活性位点的利用通常受到本体生长材料的低本征电导率的限制，从而导致差的电化学性能。在这里，开发了一种通用的策略，以提高COF基电极的能量存储能力，通过集成COF与碳纳米管（CNT）。这些COF复合材料的特征在于丰富的氧化还原活性2，7-二氨基-9，10-菲醌（DAPQ）基序、稳健的β-酮烯胺键和明确的中孔。复合材料（DAPQ-COFX-其中X = CNT的wt%）通过原位缩聚制备，并且具有在CNT表面上紧密生长的COF层的管状核-壳结构。这种协同结构设计使得能够实现上级电化学性能：DAPQ-COF 50显示95%的氧化还原活性位点利用率、长循环稳定性（在2000 mA g（-1）下3000次循环后76%的保持率）和超高倍率性能，在50 A g（-1）下具有58%的容量保持率。该速率转化为充电时间约为11 s（320 C），这意味着DAPQ-COF 50对高功率电池具有良好的前景。此外，速率能力超过了所有以前的报告含羰基的有机电极的数量级;事实上，这种功率密度和快速（放电）充电时间与电化学电容器竞争。
Covalent organic frameworks (COFs) are promising electrode materials for Li-ion batteries. However, the utilization of redox-active sites embedded within COFs is often limited by the low intrinsic conductivities of bulk-grown material, resulting in poor electrochemical performance. Here, a general strategy is developed to improve the energy storage capability of COF-based electrodes by integrating COFs with carbon nanotubes (CNT). These COF composites feature an abundance of redox-active 2,7-diamino-9,10-phenanthrenequinone (DAPQ) based motifs, robust beta-ketoenamine linkages, and well-defined mesopores. The composite materials (DAPQ-COFX-where X = wt% of CNT) are prepared by in situ polycondensation and have tube-type core-shell structures with intimately grown COF layers on the CNT surface. This synergistic structural design enables superior electrochemical performance: DAPQ-COF50 shows 95% utilization of redox-active sites, long cycling stability (76% retention after 3000 cycles at 2000 mA g(-1)), and ultra-high rate capability, with 58% capacity retention at 50 A g(-1). This rate translates to charging times of approximate to 11 s (320 C), implying that DAPQ-COF50 holds excellent promise for high-power cells. Furthermore, the rate capability outperformed all previous reports for carbonyl-containing organic electrodes by an order of magnitude; indeed, this power density and the rapid (dis)charge time are competitive with electrochemical capacitors.