Wang Mingming, Meng Yahan, Sajid Muhammad, Xie Zehui, Tong Peiyan, Ma Zhentao, Zhang Kai, Shen Dongyang, Luo Ruihao, Song Li, Wu Lihui, Zheng Xusheng, Li Xiangyang, Chen Wei
Department of Applied Chemistry, School of Chemistry and Materials Science, Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, China.
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029, China.
Angew Chem Int Ed Engl. 2024 Sep 23;63(39):e202404784. doi: 10.1002/anie.202404784. Epub 2024 Aug 25.
The aqueous zinc-iodine battery is a promising energy storage device, but the conventional two-electron reaction potential and energy density of the iodine cathode are far from meeting practical application requirements. Given that iodine is rich in redox reactions, activating the high-valence iodine cathode reaction has become a promising research direction for developing high-voltage zinc-iodine batteries. In this work, by designing a multifunctional electrolyte additive trimethylamine hydrochloride (TAH), a stable high-valence iodine cathode in four-electron-transfer I/I/I reactions with a high theoretical specific capacity is achieved through a unique amine group, Cl bidentate coordination structure of (TA)ICl. Characterization techniques such as synchrotron radiation, in situ Raman spectra, and DFT calculations are used to verify the mechanism of the stable bidentate structure. This electrolyte additive stabilizes the zinc anode by promoting the desolvation process and shielding mechanism, enabling the zinc anode to cycle steadily at a maximum areal capacity of 57 mAh cm with 97 % zinc utilization rate. Finally, the four-electron-transfer aqueous Zn-I full cell achieves 5000 stable cycles at an N/P ratio of 2.5. The unique bidentate coordination structure contributes to the further development of high-valence and high capacity aqueous zinc-iodine batteries.
水系锌碘电池是一种很有前景的储能装置，但碘正极的传统双电子反应电位和能量密度远不能满足实际应用需求。鉴于碘具有丰富的氧化还原反应，激活高价碘正极反应已成为开发高压锌碘电池的一个有前景的研究方向。在这项工作中，通过设计一种多功能电解质添加剂盐酸三甲胺（TAH），通过独特的胺基、Cl双齿配位结构（TA）ICl，在四电子转移I/I/I反应中实现了具有高理论比容量的稳定高价碘正极。利用同步辐射、原位拉曼光谱和DFT计算等表征技术验证了稳定双齿结构的机理。这种电解质添加剂通过促进去溶剂化过程和屏蔽机制来稳定锌负极，使锌负极能够在最大面积容量为57 mAh cm且锌利用率为97%的情况下稳定循环。最后，四电子转移水系Zn-I全电池在N/P比为2.5时实现了5000次稳定循环。独特的双齿配位结构有助于高价高容量水系锌碘电池的进一步发展。
