湖南大学梁宵团队报道了水锌电池的高能高价有机碘电化学。相关研究成果发表在2024年8月27日出版的《美国化学会杂志》。

高价有机碘化合物在有机合成中得到了广泛的应用，尽管与无机碘相比，它们的理论氧化还原电位很高，但它们的电化学性能仍未得到探索，无机碘主要依赖于电池应用中的I^-/I0氧化还原对。

该文中，研究人员首次使用最简单的碘苯（PhI）作为模型化合物，建立了高价有机碘在ZnCl₂水电解质中的基本氧化还原机制。验证了PhI到PhICl₂的转变是一个单步可逆反应，能够实现I⁺/I³⁺氧化还原化学的双电子转移（1.9 V vs Zn2+/Zn），具有高容量（基于PhI422 mAh giodine^–1和262.6 mAh g^–1）和高理论能量密度（801.8 Wh kg^–1）。

研究还阐明了这种有机碘电化学在各种PhI衍生物的全局反应性方面表现出丰富的可调性，包括多种碘取代的异构体和功能取代基。此外，稳定阴离子配体影响三价有机碘化合物的可逆性和稳定性。通过限制副反应和提高三价有机碘在低温下的稳定性，锌PhI电池证明了I⁺/I³⁺转化的可行性，并在400次循环中保持了稳定的性能。

该项工作弥合了高价有机碘化学和电池技术之间的差距，突出了未来高性能电池应用的潜力。

附：英文原文

Title: Energetic Hypervalent Organoiodine Electrochemistry for Aqueous Zinc Batteries

Author: Pengjie Jiang, Tingting Liu, Chengjun Lei, Huijian Wang, Jinye Li, Min Shi, Chen Xu, Xin He, Xiao Liang

Issue&Volume: August 27, 2024

Abstract: 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–/I0 redox couple in battery applications. Here, the fundamental redox mechanism of hypervalent organoiodine in a ZnCl2 aqueous electrolyte is established for the first time using the simplest iodobenzene (PhI) as a model compound. We validated that the PhI to PhICl2 transition is a single-step and reversible reaction, enabling two-electron transfer of I+/I3+ redox chemistry (1.9 V vs Zn2+/Zn) with high capacity (422 mAh giodine–1, and 262.6 mAh g–1 based on PhI) and high theoretical energy density (801.8 Wh kg–1). 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+/I3+ 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.

DOI: 10.1021/jacs.4c08145

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c08145