Yu Xiaoyu, Chen Ming, Li Zhengang, Tan Xi, Zhang Haitang, Wang Junhao, Tang Yonglin, Xu Juping, Yin Wen, Yang Yang, Chao Dongliang, Wang Fei, Zou Yeguo, Feng Guang, Qiao Yu, Zhou Haoshen, Sun Shi-Gang
State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
J Am Chem Soc. 2024 Jun 26;146(25):17103-17113. doi: 10.1021/jacs.4c02558. Epub 2024 Jun 13.
Understanding the interfacial hydrogen evolution reaction (HER) is crucial to regulate the electrochemical behavior in aqueous zinc batteries. However, the mechanism of HER related to solvation chemistry remains elusive, especially the time-dependent dynamic evolution of the hydrogen bond (H-bond) under an electric field. Herein, we combine in situ spectroscopy with molecular dynamics simulation to unravel the dynamic evolution of the interfacial solvation structure. We find two critical change processes involving Zn-electroplating/stripping, including the initial electric double layer establishment to form an HO-rich interface (abrupt change) and the subsequent dynamic evolution of an H-bond (gradual change). Moreover, the number of H-bonds increases, and their strength weakens in comparison with the bulk electrolyte under bias potential during Zn desolvation, forming a diluted interface, resulting in massive hydrogen production. On the contrary, a concentrated interface (H-bond number decreases and strength enhances) is formed and produces a small amount of hydrogen during Zn solvation. The insights on the above results contribute to deciphering the H-bond evolution with competition/corrosion HER during Zn-electroplating/stripping and clarifying the essence of electrochemical window widened and HER suppression by high concentration. This work presents a new strategy for aqueous electrolyte regulation by benchmarking the abrupt change of the interfacial state under an electric field as a zinc performance-enhancement criterion.
了解界面析氢反应（HER）对于调控水系锌电池的电化学行为至关重要。然而，与溶剂化化学相关的HER机理仍不明确，尤其是电场作用下氢键（H键）随时间的动态演变。在此，我们将原位光谱与分子动力学模拟相结合，以揭示界面溶剂化结构的动态演变。我们发现了两个涉及锌电镀/剥离的关键变化过程，包括最初形成富含HO的界面以建立双电层（突变）以及随后氢键的动态演变（渐变）。此外，在锌去溶剂化过程中，与本体电解质相比，在偏置电位下氢键数量增加，但其强度减弱，形成稀释界面，导致大量产氢。相反，在锌溶剂化过程中形成浓缩界面（氢键数量减少且强度增强）并产生少量氢气。上述结果的见解有助于解读锌电镀/剥离过程中具有竞争/腐蚀析氢反应的氢键演变，并阐明高浓度拓宽电化学窗口和抑制析氢反应的本质。这项工作提出了一种新的水系电解质调控策略，通过将电场作用下界面状态的突变作为锌性能增强的标准进行基准测试。
