Lattice Water Deprotonation Enables Potassium‐Ion Chemistries

作者：Huan Xu, Nanzhong Wu, Bifa Ji, Jinghua Cai, Wenjiao Yao, Zihang Wang, Y X Zhang, Xinyuan Zhang, Shu Guo, Xiaolong Zhou, Pinit Kidkhunthod, Yongping Zheng, Yongbing Tang · 发表于：Angewandte Chemie International Edition · 年份：2025 · DOI：10.1002/anie.202503904 · 被引用次数：14 · 研究领域：Electrocatalysts for Energy Conversion、Electrochemical Analysis and Applications、Ammonia Synthesis and Nitrogen Reduction

Abstract Electrochemical water splitting is a key process in clean energy applications and usually occurs on the surface of catalytic materials. Here, we report the anomalous partial water splitting, namely, water deprotonation behavior within the lattice of hydrated materials modeled by Fe 1‐ x Mg x (C 2 O 4 ) • 2H 2 O ( x ≈ 0.25–0.43), which triggers the otherwise inactive framework into an excellent cathode material for potassium ion storage. Density functional theory suggests that redox‐active lattice Fe sites can split crystal water into hydroxyls and hydrogens in the initial charge, rendering thereafter reversible K‐ion chemistries, whereas lattice Mg sites are inactive but stabilize the entire framework. Our experiments validated the as‐predicted electrochemical behavior, and the isotopic tracing unambiguously confirmed the hydrogen evolution from crystal water. This intriguing “water deprotonation in lattice” phenomenon may open a new path for the design of cathode materials by electrolysis‐assisted electrochemistry.