1成果简介
　　本文，江西理工大学陈军 教授团队在《ACS Appl. Mater. Interfaces》期刊发表名为“In Situ Composites of Phthalocyanine-Based Covalent Organic Frameworks with Carbon Cloth as a Flexible Binder-Free Anode Material for High-Performance Lithium/Sodium-Ion Batteries”的论文，研究利用原位席夫碱反应在碳布（CC）上生长酞菁共价有机框架（TFPB-NiPc），从而获得复合材料 TFPB-NiPc@CC，并将其用作无粘结剂和导电剂的锂/镎离子电池的阳极，提高了活性材料的负载量。
　　此外，CC 在降低酞菁框架（Pc-COFs）堆叠效应的同时，还起到了良好的导电骨架作用，从而使 TFPB-NiPc 在原位合成过程中实现了自剥离效应。这种策略缩短了锂的迁移路径，有效提高了锂在电极中的迁移率。因此，TFPB-NiPc@CC 电极不仅改善了高容量和长周期稳定性的电化学性能，还表现出卓越的柔韧性和折叠稳定性。在 200 mA/g 的条件下，TFPB-NiPc@CC 电极的比容量为 1090.2 mA h/g；在循环 500 次后，TFPB-NiPc@CC 电极的比容量还能保持在 994.5 mA h/g，保持率为 91.2%，这些指标都远远高于 TFPB-NiPc 电极。此外，TFPB-NiPc@CC 在镍离子电池中也表现出较高的比容量和稳定的循环行为。本研究设计的策略为制备实用的高性能柔性有机负极材料提供了新的思路和方法。
　　2图文导读 

　　图1. Synthetic routes of TFPB-NiPc without CC and TFPB-NiPc@CC containing CC under the same conditions (a); schematic diagram of the process of TFPB-NiPc loading on CC and optimization of TFPB-NiPc frame structure (b).

　　图2. Infrared spectra of TFPB-NiPc, TFPB-NiPc@CC, TFPB, and TA-NiPc (a,b); Raman spectra of TFPB-NiPc and TFPB-NiPc@CC (c); XRD spectra of TFPB-NiPc, TFPB-NiPc@CC, and CC (d); TFPB-NiPc@CC, CC, and TFPB-NiPc nitrogen adsorption–desorption curves (e–g) and pore size distribution plots (h,i).

　　图3. SEM images of the synthesized materials: CC (a,b), TFPB-NiPc@CC (c), TFPB-NiPc (d), and TFPB-NiPc@CC after sonication for 30 min (e,f); EDS images of the materials: TFPB-NiPc (g1–g4), TFPB-NiPc@CC (h1–h4). Transmission electron micrographs (TEM) images of the synthesized materials: TFPB-NiPc (i,k), TFPB-NiPc@CC (j,l), the inset of (i) shows the SAED pattern of TFPB-NiPc.

　　图4. CV curves of TFPB-NiPc (a), TFPB-NiPc@CC (b) as lithium-ion battery electrodes at a scan rate of 0.1 mV/s; comparison of the first charge/discharge of TFPB-NiPc and TFPB-NiPc@CC electrodes (c); charge/discharge curves of TFPB-NiPc (d) and TFPB-NiPc@CC (e) electrodes at the first, 100th, 200th, 300th, 400th, and 450th revolutions, respectively; rate diagrams of TFPB-NiPc and TFPB-NiPc@CC electrodes (f); long-cycle plots of TFPB-NiPc and TFPB-NiPc@CC electrodes at 200 mA/g current density (g); and electrochemical impedance spectra of TFPB-NiPc and TFPB-NiPc@CC as lithium-ion battery electrodes at different cycles (h–k).

　　图5. CV curves of TFPB-NiPc@CC as lithium-ion battery electrodes at different scan rates (a); log(v) vs log(i) scatter plots of the cathodic and anodic peaks and the fitted curves (b); linear fit plot of peak current versus scan rate (c); linear fit plot of peak current versus square root of scan rate (d); different histogram of pseudo capacitance contribution at different sweep speeds (e); diagram of pseudocapacitance duty cycle at 0.6 mV/s sweep rate (f); GITT curve of TFPB-NiPc (g); and GITT curve and diffusion coefficient of TFPB-NiPc@CC (h).

　　图6. C 1s XPS spectra of TFPB-NiPc and TFPB-NiPc@CC electrodes of lithium-ion batteries: pristine (a1,b1), discharged (a2,b2) and charged (a3,b3); N 1s XPS spectra of TFPB-NiPc and TFPB-NiPc@CC electrodes of lithium-ion batteries: pristine (c1,d1), discharged (c2,d2), and charged (c3,d3).

　　图7. HOMO–LUMO gap of TFPB-NiPc (a); comparison of HOMO/LUMO energies of TFPB-NiPc with other organics (b); schematic of lithium intercalated in TFPB-NiPc (c); compositional diagram of flexible pouch battery (d); and flexible test of the NCM811||TFPB-NiPc@CC pouch cell in different bending states (flat, 90° bend and 180° bend) (e–g).
　　3小结
　　综上所述，针对 Pc-COFs 导电性差、堆叠效应严重等问题，通过原位席夫碱反应成功合成了具有超高容量的 TFPB-NiPc@CC 作为锂离子电池和钠离子电池的负极材料。TFPB-NiPc 材料较低的 LUMO 值和 HOMO 值有利于其接受电子，从而表现出更好的电化学性能。在 CC 上负载 TFPB-NiPc 后，堆叠效应的减弱和比表面积的增加进一步提高了其电化学性能。TFPB-NiPc 与 CC 之间的强接触促进了电荷转移，加快了氧化还原反应的速率。CC 作为集电体提供了良好的导电骨架，不仅降低了 Pc-COFs 的堆叠效应，还暴露了更多的活性位点，从而更有利于锂的传输和扩散。电化学结果表明，TFPB-NiPc@CC 电极具有超高的容量和优异的循环稳定性。复合材料的初始特定放电容量可达 1081.67 mA h/g；即使循环 500 次后，容量仍可保持在 994.5 mA h/g。这项工作不仅为有机负极材料的设计提供了宝贵的经验，也为高性能锂离子柔性电极材料的开发提供了宝贵的经验。
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