Wang Simin, Guo Qifei, Liu Haoran, Zhang Longhai, Zhang Chaofeng, Zhou Tengfei, Ma Quanwei, Li Hongbao, Wang Rui, Zheng Yang
Institutes of Physical Science and Information Technology, School of Materials Science and Engineering, Leibniz International Joint Research Center of Materials Sciences of Anhui Province, Anhui Province Key Laboratory of Environment-Friendly Polymer Materials, Key Laboratory of Structure and Functional Regulation of Hybrid Material (Ministry of Education), Anhui University Hefei 230601 China
The State Key Laboratory of Refractories and Metallurgy, Institute of Advanced Materials and Nanotechnology, Wuhan University of Science and Technology Wuhan 430081 China
Chem Sci. 2023 Dec 7;15(3):1051-1060. doi: 10.1039/d3sc05843c. eCollection 2024 Jan 17.
Organic small-molecule compounds have become promising cathode materials for high-performance lithium-ion batteries (LIBs) due to their high theoretical capacity, efficient utilization of active sites, low cost, and sustainability. However, severe dissolution and poor electronic conductivity limit their further practical applications. Herein, we have synthesized an insoluble organic small molecule, ferrocenyl-3-(λ-azazyl) pyrazinyl [2,3-] [1,10] phenanthrolino-2-amine (FCPD), by grafting ferrocene onto pyrazino[2,3-f] [1,10] phenanthroline-2,3-diamine (PPD). The combination of ferrocene (p-type Fe moiety) and PPD (n-type C[double bond, length as m-dash]N groups) in a bipolar manner endows the target FCPD cathode with an increased theoretical capacity and a wide voltage window. The highly conjugated π-π aromatic skeleton inside enhances FCPD's electron delocalization and promotes strong interaction between FCPD units. Additionally, the mesoporous structure within the FCPD can provide numerous electroactive sites, contact area, and ion diffusion channels. Benefiting from the bipolar feature, aromatic, and mesoporous structure, the FCPD cathode demonstrates a large capacity of 250 mA h g at 0.1 A g, a long lifespan of 1000 cycles and a high-rate capability of 151 mA h g at 5 A g along with a wide voltage window (1.2-3.8 V). Additionally, synchrotron FT-IR and XPS reveal its dual ion storage mechanism in depth. Our findings provide essential insights into exploring the molecular design of advanced organic small molecules.
有机小分子化合物因其高理论容量、活性位点的有效利用、低成本和可持续性，已成为高性能锂离子电池（LIBs）颇具前景的阴极材料。然而，严重的溶解问题和较差的电子导电性限制了它们的进一步实际应用。在此，我们通过将二茂铁接枝到吡嗪并[2,3-f][1,10]菲咯啉-2,3-二胺（PPD）上，合成了一种不溶性有机小分子，即二茂铁基-3-(λ-氮杂基)吡嗪基[2,3-][1,10]菲咯啉-2-胺（FCPD）。二茂铁（p型Fe部分）和PPD（n型C=N基团）以双极方式结合，赋予目标FCPD阴极更高的理论容量和更宽的电压窗口。内部高度共轭的π-π芳香骨架增强了FCPD的电子离域，并促进了FCPD单元之间的强相互作用。此外，FCPD中的介孔结构可以提供大量的电活性位点、接触面积和离子扩散通道。受益于双极特性、芳香性和介孔结构，FCPD阴极在0.1 A g下表现出250 mA h g的大容量、1000次循环的长寿命以及在5 A g下151 mA h g的高倍率性能，同时具有宽电压窗口（1.2 - 3.8 V）。此外，同步辐射傅里叶变换红外光谱和X射线光电子能谱深入揭示了其双离子存储机制。我们的研究结果为探索先进有机小分子的分子设计提供了重要见解。
