厦门大学乔羽团队报道了水溶液锌电池的动态溶剂化化学及析氢机理。相关研究成果发表在2024年6月13日出版的《美国化学会杂志》。

了解界面析氢反应（HER）对于调节水性锌电池的电化学行为至关重要。然而，HER与溶剂化化学相关的机制仍然难以捉摸，尤其是氢键（氢键）在电场下的时间依赖动态演化。

该文中，研究人员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化。研究发现了两个涉及锌电镀/剥离的关键变化过程，包括形成富H₂O界面的初始双电层建立（突变）和随后氢键的动态演化（渐变）。此外，在Zn²⁺去溶剂化过程中，与偏压下的体电解质相比，氢键的数量增加，其强度减弱，形成稀释的界面，导致大量的氢气产生。

相反，在Zn²⁺溶剂化过程中，形成了集中的界面（氢键数减少，强度增强）并产生少量的氢。对上述结果的深入了解有助于破解Zn电镀/剥离过程中H键与竞争/腐蚀HER的演变，并阐明高浓度电化学窗口加宽和HER抑制的本质。

该项工作通过将电场下界面状态的突变作为锌性能增强标准，提出了一种新的水电解质调节策略。

附：英文原文

Title: Unlocking Dynamic Solvation Chemistry and Hydrogen Evolution Mechanism in Aqueous Zinc Batteries

Author: Xiaoyu Yu, Ming Chen, Zhengang Li, Xi Tan, Haitang Zhang, Junhao Wang, Yonglin Tang, Juping Xu, Wen Yin, Yang Yang, Dongliang Chao, Fei Wang, Yeguo Zou, Guang Feng, Yu Qiao, Haoshen Zhou, Shi-Gang Sun

Issue&Volume: June 13, 2024

Abstract: 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 H2O-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 Zn2+ 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 Zn2+ 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.

DOI: 10.1021/jacs.4c02558

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c02558