Mei Binhua, Hou Yanjun, Song Boxuan, Li Yan, Liu Zixuan, Niu Haijun
Key Laboratory of Chemistry, Chemical Engineering and Materials, High-Quality Technology Conversion, Heilongjiang Province, and School of Chemistry and Chemical Engineering, Heilongjiang University, Harbin 150080, P. R. China.
Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, and Department of Macromolecular Science and Engineering, School of Chemistry and Chemical Engineering, Heilongjiang University, Harbin 150080, P. R. China.
ACS Appl Mater Interfaces. 2025 Jan 15;17(2):3393-3403. doi: 10.1021/acsami.4c18861. Epub 2025 Jan 1.
Organic cathode materials are widely considered as highly promising for aqueous zinc-ion batteries (AZIBs) due to their tunable properties, low cost, and ease of processing and synthesis. Benzothiadiazoles have demonstrated significant potential as organic electrode materials in AZIBs, owing to their strong electron-accepting capabilities and the presence of multiple reversible redox sites in anthraquinone. In this study, we designed a polymer, poly(2-methyl-6-(7-methyl-5,6-dinitrobenzo[][1,2,5]thiadiazol-4-yl)anthracene-9,10-dione) (PBDQ), with multielectron transfer capability through a copolymerization approach. Additionally, we synthesized another polymer, poly2,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)anthracene-9,10-dione(PBDQ-N), by introducing two electron-withdrawing nitro groups on the aromatic ring of benzothiadiazole. The introduction of nitro groups, with their unique electronic properties, enhances electron delocalization and increases the number of electrochemically active sites, thereby promoting faster zinc-ion insertion/extraction reactions. Experimental results show that both PBDQ and PBDQ-N exhibit excellent electrochemical properties due to the abundance of active sites and extended π-conjugation. Among them, PBDQ-N demonstrates outstanding performance, including an ultrahigh specific capacity of 446.2 mAh g at 0.1 A g and excellent cycle life exceeding 20,000 cycles at 10 A g. Moreover, the lower lowest-unoccupied molecular orbital (LUMO) energy level and improved conductivity of PBDQ-N provide a fast electron transfer rate, resulting in a higher Zn diffusion coefficient (3.47 × 10-2.6 × 10 cm s) and exceptional rate performance (234.6 mAh g at 10 A g). Theoretical calculations and ex situ characterizations confirm that C═O, C═N, and N═O groups all participate as active sites in Zn storage. This work highlights how molecular design and the introduction of functional groups, such as nitro groups, can effectively regulate the electrochemical properties of organic polymers in AZIBs. It also demonstrates the impact of these strategies on the electrochemical performances of these materials when they are used as cathodes in aqueous zinc-ion batteries.
有机阴极材料因其可调节的性能、低成本以及易于加工和合成，被广泛认为是水系锌离子电池（AZIBs）极具前景的材料。苯并噻二唑已展现出作为AZIBs中有机电极材料的巨大潜力，这归因于其强大的吸电子能力以及蒽醌中多个可逆氧化还原位点的存在。在本研究中，我们通过共聚方法设计了一种具有多电子转移能力的聚合物，聚（2-甲基-6-（7-甲基-5,6-二硝基苯并[][1,2,5]噻二唑-4-基）蒽-9,10-二酮）（PBDQ）。此外，我们通过在苯并噻二唑的芳环上引入两个吸电子硝基，合成了另一种聚合物，聚2,6-双（4,4,5,5-四甲基-1,3,2-二氧硼杂环戊烷-2-基）蒽-9,10-二酮（PBDQ-N）。硝基独特的电子性质增强了电子离域，并增加了电化学活性位点的数量，从而促进了更快的锌离子插入/脱出反应。实验结果表明，由于活性位点丰富且具有扩展的π共轭结构，PBDQ和PBDQ-N均表现出优异的电化学性能。其中，PBDQ-N展现出卓越的性能，包括在0.1 A g时具有446.2 mAh g的超高比容量，以及在10 A g时超过20,000次循环的优异循环寿命。此外，PBDQ-N较低的最低未占据分子轨道（LUMO）能级和改善的导电性提供了快速的电子转移速率，导致更高的锌扩散系数（3.47×10 -2.6×10 cm s）和出色的倍率性能（在10 A g时为234.6 mAh g）。理论计算和非原位表征证实，C═O、C═N和N═O基团均作为锌存储的活性位点参与其中。这项工作突出了分子设计以及引入硝基等官能团如何有效调节AZIBs中有机聚合物的电化学性能。它还展示了这些策略在这些材料用作水系锌离子电池阴极时对其电化学性能的影响。
