Well-Aligned Liquid Crystal Interface and Expanded Solvation Sheath Accelerate Zn<sup>2+</sup> Desolvation Kinetics for Stable Zinc Batteries
Chen Li, Yuxuan Liu, Jiangwen Liu, Mili Liu, Yulong Gao, Xinyu Wang, Yongshuo Zheng, Jun Liu, Longtao Ma, Liuzhang Ouyang, Min Zhu
Abstract
The straightforward processing and assembly of zinc batteries enable large-scale production and cost-effective energy storage solutions. However, nonuniform Zn plating and parasitic reactions impede practical deployment, which can be addressed through advanced interfacial modifications and enhanced Zn 2+ transport kinetics. Herein, we developed a trace additive based on a tailored liquid crystal molecule (4-pentyl-4′-cyanobiphenyl, 5CB), which preferentially adsorbs onto the zinc surface to form a dynamic ordered interfacial layer and modulate the Zn 2+ solvation shell due to its self-assembling and anisotropic properties. The interfacial layer inhibits solvent decomposition and side reactions, while the expanded solvation shell weakens Zn 2+ interactions with both solvents and anion, lowering the desolvation barrier and enabling fast, uniform Zn 2+ transport. Consequently, the Zn 2+ transfer number increases from 0.29 to 0.71, and epitaxial deposition of Zn 2+ along the (002) crystal plane is promoted, ensuring uniform zinc deposition. Benefiting from the liquid crystal interfacial layer, the Zn∥Zn symmetric cell demonstrates exceptional cycling stability for up to 2000 h, surpassing that without 5CB (only 400 h) while asymmetric Zn∥Ti cells with 5CB maintain >99.1% Coulombic efficiency after 1100 cycles, compared to rapid degradation without 5CB. The Zn∥PANI full cells deliver 157.6 mAh g –1 at 0.1 A g –1, retaining 130.1 mAh g –1 at a high current density of 5 A g –1, and achieves 86% capacity retention over 500 cycles. These findings highlight the effectiveness of liquid crystal interfacial engineering in improving Zn-ion transport kinetics and stabilizing Zn anodes, paving the way for high-performance, long-lifetime zinc batteries.