Deng Wenjing, Deng Zhiping, Zhang Xuzi, Chen Yimei, Feng Renfei, Li Ge, Wang Xiaolei
Department of Chemical and Materials Engineering, University of Alberta, 9211-116 Street NW., Edmonton, Alberta, T6G 1H9, Canada.
Department of Mechanical Engineering, University of Alberta, 9211-116 Street NW., Edmonton, Alberta, T6G 1H9, Canada.
Angew Chem Int Ed Engl. 2025 Jan 21;64(4):e202416482. doi: 10.1002/anie.202416482. Epub 2024 Nov 18.
Eutectic electrolytes hold promise for aqueous zinc metal batteries in sustainable energy storage chemistries, yet improvement from perspective of molecule configurational engineering are ambiguous. Herein, we propose design strategy of increasing asymmetric molecular geometry in organic ligands to regulate frustrated coordination and disordered structure for eutectic electrolytes toward enhanced zinc metal batteries. The introduced asymmetry in eutectic component gives rise to relatively weak coordination strength and configurational disorder interaction among cation-anion-ligand, leading to suppressed local aggregation, steady eutectic phase and improved Zn diffusion kinetics. Such highly frustrated coordination state also enables disruption of hydrogen bonding network and reinforcement of anion participation, which results in confined side reactions, decreased water activity and the formation of inorganic-enriched solid electrolyte interphase. In comparison to highly symmetric ligands, asymmetric ligand-involved eutectic electrolytes with configurational disorder deliver high Coulombic efficiency of 99.4 %, stabilized Zn plating/stripping of 5000 h and impressive rate capability even under harsh conditions such as small N/P, low temperature. The rationale in this work advances the deep understanding of asymmetric molecular engineering in eutectic electrolytes and showcases suitability of frustrated coordination to achieve high-performance zinc metal batteries.
低共熔电解质在可持续储能化学领域的水系锌金属电池中具有应用前景，然而从分子构型工程的角度来看，其改进尚不明确。在此，我们提出了一种设计策略，即增加有机配体中的不对称分子几何结构，以调节低共熔电解质的受挫配位和无序结构，从而提升锌金属电池性能。在低共熔组分中引入的不对称性导致阳离子 - 阴离子 - 配体之间的配位强度相对较弱以及构型无序相互作用，进而抑制了局部聚集、稳定了低共熔相并改善了锌的扩散动力学。这种高度受挫的配位状态还能够破坏氢键网络并增强阴离子的参与度，从而限制副反应、降低水活性并形成富含无机成分的固体电解质界面。与高度对称的配体相比，具有构型无序的含不对称配体的低共熔电解质即使在诸如低氮磷比、低温等苛刻条件下也能实现99.4%的高库仑效率、5000小时稳定的锌电镀/剥离以及出色的倍率性能。这项工作中的原理加深了对低共熔电解质中不对称分子工程的理解，并展示了受挫配位对于实现高性能锌金属电池的适用性。
