Biomass-Derived Ion-Selective Binder Modulates Zn2+ Solvation Enabling High-Capacity Cathodes in Aqueous Zinc Batteries

Authors:Jiaxian Zheng, Yangyi Zhao, Abdullahi Bello Umar, Xiangfeng Lin,* Chaoqun Zhang,* Xinxiang Zhang, Yusuke Asakura, Shude Liu,* Yusuke Yamauchi, and Zhanhui Yuan*

Abstract:The electrochemical performance of aqueous zinc batteries (AZBs) critically relies on advanced binders to regulate the solvation structure of hydrated Zn2+ and accelerate the redox kinetics at the cathode interface. However, conventional hydrophobic polyvinylidene fluoride (PVDF) binders fail to achieve this goal due to their weak interactions with H2O and Zn2+. Here, we present a bioinspired sulfate-rich polysaccharide binder network derived from marine ι- carrageenan (CAG), which mimics biological ion channels to enable selective ion coordination and dynamic hydration regulation. By establishing dual ion-selective coordination sites, the zincophilic ─OSO3- and hydrophilic ─OH groups of CAG form Zn2+─OSO3- and H2O─OH interactions, effectively disrupting the primary solvation shell of Zn2+─H2O and accelerating Zn2+ desolvation kinetics, thereby enabling adaptive ion transport across the cathode interface. Consequently, Zn||CAG@Mn0.15V2O5·nH2O batteries deliver an ultrahigh capacity of 421 mAh g-1 at 0.6 A g-1, which is 76% higher than PVDF-based counterparts (239 mAh g-1). This water-processable binder demonstrates universal applicability across various cathode materials (e.g., MnO2, V2O5, and organics), providing a green, scalable solution for high-performance AZBs. This study establishes a biomimetic binder design paradigm, where sulfate-hydroxyl dual coordination emulates biological ion transport, enabling precise regulation of Zn2+ solvation and interfacial chemistry.

DOI:doi.org/10.1002/anie.202525803

Angew. Chem. Int. Ed. 2026, e25803