构建多层 COF@CNT 复合材料作为低成本 K 离子电池的超高倍率阴极,ACS Applied Materials & Interfaces

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构建多层 COF@CNT 复合材料作为低成本 K 离子电池的超高倍率阴极
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2022-06-27 , DOI: 10.1021/acsami.2c04831
Ju Duan ₁ , Wenting Wang ₁ , Degui Zou ₁ , Jing Liu ₂ , Na Li ₂ , Junying Weng _{1,

3} , Li-Ping Xu ₂ , Ying Guan ₄ , Yongjun Zhang ₄ , Pengfei Zhou ₂

Affiliation

^{钾离子电池（PIB）由于资源丰富且K +} /K的氧化还原电位低，在大规模储能方面引起了极大的兴趣。^{然而，正极材料中较大的 K +}离子半径导致的大体积变化和缓慢的动力学仍然是 PIBs 面临的关键挑战。在此，我们构建了与羧化碳纳米管（DAAQ-COF@CNT）集成的少层共价有机框架作为 PIB 的阴极材料。合成的DAAQ-COF@CNT具有大量的活性位点、稳定的导电骨架和合适的纳米孔表面积，可呈现高导电性，缩短离子/电子扩散距离，加速K ⁺扩散。因此，DAAQ-COF@CNT在 0.1 A g ^-1时具有 157.7 mAh g ^-1的高可逆容量，在 1 A g ^{-1时具有 111.2 mAh g}^-1的优异倍率性能，以及在 0.5 A g ^–1下 500 次循环后容量保持率为 77.6% 。异位 X 射线光电子能谱、傅里叶变换红外光谱和理论模拟的综合表征揭示了 DAAQ-COF@CNT 的存储机理是基于电活性 C=O 基团与 K ^{+之间的可逆反应。}在两个连续的步骤中。这项工作为 PIBs 提供了一种有前途的高性能正极材料，并鼓励开发用于 PIBs 的新型共价有机框架。

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Construction of a Few-Layered COF@CNT Composite as an Ultrahigh Rate Cathode for Low-Cost K-Ion Batteries

Potassium-ion batteries (PIBs) are attracting great interest for large-scale energy storage owing to the abundant resources and low redox potential of K⁺/K. However, the large volume changes and slow kinetics caused by the larger ionic radius of K⁺ for cathode materials remain a critical challenge for PIBs. Herein, we construct few-layered covalent organic frameworks integrated with carboxylated carbon nanotubes (DAAQ-COF@CNT) as cathode materials for PIBs. The synthesized DAAQ-COF@CNT features numerous active sites, a stable conductive framework, and an appropriate surface area with nanopores, which can render high electrical conductivity, shorten the ion/electron diffusion distance, and accelerate K⁺ diffusion. In consequence, the DAAQ-COF@CNT delivers a high reversible capacity of 157.7 mAh g^–1 at 0.1 A g^–1, an excellent rate capability of 111.2 mAh g^–1 at 1 A g^–1, and a long cycling stability of 77.6% capacity retention after 500 cycles at 0.5 A g^–1. The integrated characterization of ex situ X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and theoretical simulation discloses that the storage mechanism of DAAQ-COF@CNT is based on the reversible reaction between electroactive C═O groups and K⁺ during two successive steps. This work provides a promising high-performance cathode material for PIBs and encourages the development of new types of covalent organic frameworks for PIBs.

更新日期：2022-06-27

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