Liu Yangyang, Zhang Longhai, Liu Ling, Ma Quanwei, Wang Rui, Xiong Peng, Li Hongbao, Zhang Shilin, Hao Junnan, Zhang Chaofeng
School of Materials Science and Engineering, Institutes of Physical Science and Information Technology, Leibniz International Joint Research Center of Materials Sciences of Anhui Province, Anhui University, Hefei, 230601, China.
School of Chemical Engineering, The University of Adelaide, Adelaide, 5005, Australia.
Adv Mater. 2025 Feb 16:e2415979. doi: 10.1002/adma.202415979.
The practical development of aqueous zinc-iodine (Zn-I) batteries is greatly hindered by the low energy density resulting from conventional I/I conversion and the limited temperature tolerance. Here, a temperature-insensitive polycationic hydrogel electrolyte borax-bacterial cellulose / p(AM-co-VBIMBr) (denoted as BAVBr) for achieving an energy-dense cascade aqueous Zn-I battery over a wide temperature range from -50 to 50 °C is designed. A comprehensive investigation, combining advanced spectroscopic investigation and DFT calculations, has revealed that the presence of Br species in the gel electrolyte facilitates the conversion reaction of Br/Br. Simultaneously, it activates the high voltage I/I redox reaction through interhalogen formation. Consequently, sequential and highly reversible redox reactions involving I/I, I/I, and Br/Br are achieved with the assistance of -NR units in BAVBr, effectively suppressing interhalogen hydrolysis in aqueous electrolyte. The cascade reactions lead to a high area capacity of 0.76 mAh cm at a low I loading of 1 mg cm or 760 mAh g based on the mass of iodine, demonstrating exceptional long-term cycling stability over a wide temperature range from -50 to 50 °C. This study offers valuable insights into the rational design of electrolytes for high-energy aqueous batteries, specifically tailored for wide-temperature operation.
传统的碘/碘化物转换所导致的低能量密度以及有限的温度耐受性极大地阻碍了水系锌-碘（Zn-I）电池的实际发展。在此，设计了一种对温度不敏感的聚阳离子水凝胶电解质硼砂-细菌纤维素/p（AM-co-VBIMBr）（记为BAVBr），用于在-50至50°C的宽温度范围内实现能量密集型级联水系Zn-I电池。一项结合先进光谱研究和密度泛函理论计算的综合研究表明，凝胶电解质中溴物种的存在促进了Br/Br的转换反应。同时，它通过卤素间化合物的形成激活了高电压的I/I氧化还原反应。因此，在BAVBr中-NR单元的辅助下，实现了涉及I/I、I/I和Br/Br的连续且高度可逆的氧化还原反应，有效抑制了水系电解质中卤素间化合物的水解。这些级联反应在低碘负载量为1mg/cm²时实现了0.76mAh/cm²的高面积容量，或基于碘质量的760mAh/g，在-50至50°C的宽温度范围内展现出卓越的长期循环稳定性。这项研究为高能水系电池电解质的合理设计提供了宝贵的见解，特别是针对宽温度运行进行了专门定制。
