Jiang Pengjie, Liu Tingting, Lei Chengjun, Wang Huijian, Li Jinye, Shi Min, Xu Chen, He Xin, Liang Xiao
State Key Laboratory of Chem/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
J Am Chem Soc. 2024 Sep 11;146(36):25108-25117. doi: 10.1021/jacs.4c08145. Epub 2024 Aug 27.
Hypervalent organoiodine compounds have been extensively utilized in organic synthesis, yet their electrochemical properties remain unexplored despite their theoretically high redox potential compared with inorganic iodine, which primarily relies on the I/I redox couple in battery applications. Here, the fundamental redox mechanism of hypervalent organoiodine in a ZnCl aqueous electrolyte is established for the first time using the simplest iodobenzene (PhI) as a model compound. We validated that the PhI to PhICl transition is a single-step and reversible reaction, enabling two-electron transfer of I/I redox chemistry (1.9 V vs Zn/Zn) with high capacity (422 mAh g, and 262.6 mAh g based on PhI) and high theoretical energy density (801.8 Wh kg). It was also elucidated that such organoiodine electrochemistry exhibits rich tunability in terms of the global reactivity of various PhI derivatives, including multiple iodine-substituted isomers and functional substituents. Additionally, the stabilizing anion ligands affect the reversibility and stability of trivalent organoiodine compounds. By limiting side reactions and improving the stability of trivalent organoiodine at low temperatures, the zinc-PhI battery demonstrated the feasibility of I/I conversion and sustained stable performance over 400 cycles. This work bridges the gap between hypervalent organoiodine chemistry and battery technology, highlighting the potential for future high-performance battery applications.
高价有机碘化合物已在有机合成中得到广泛应用，然而，尽管与无机碘相比，它们在理论上具有较高的氧化还原电位（无机碘在电池应用中主要依赖于I/I氧化还原对），但其电化学性质仍未得到探索。在此，首次以最简单的碘苯（PhI）为模型化合物，建立了高价有机碘在ZnCl水系电解质中的基本氧化还原机制。我们验证了PhI向PhICl的转变是一个单步可逆反应，能够实现I/I氧化还原化学的双电子转移（相对于Zn/Zn为1.9 V），具有高容量（422 mAh g，基于PhI为262.6 mAh g）和高理论能量密度（801.8 Wh kg）。还阐明了这种有机碘电化学在各种PhI衍生物的整体反应性方面表现出丰富的可调性，包括多个碘取代异构体和官能团取代基。此外，稳定的阴离子配体影响三价有机碘化合物的可逆性和稳定性。通过限制副反应并提高三价有机碘在低温下的稳定性，锌- PhI电池展示了I/I转换的可行性，并在400次循环中保持稳定性能。这项工作填补了高价有机碘化学与电池技术之间的空白，突出了其在未来高性能电池应用中的潜力。
