Synchronous Reshaping Dual Helmholtz Planes via Molecular Structure Mediation for Robust Zn Metal Batteries

ABSTRACT Molecular engineering of electrolyte additives has been extensively explored to reconfigure the electric double layer (EDL) for improving the stability and interfacial kinetics of Zn metal anodes. However, achieving simultaneous regulation of both the inner and outer Helmholtz planes (IHP/OHP) through a simple strategy, along with molecularly understanding of how additive configuration dictates the IHP/OHP structure, remains inadequately addressed. In contrast to conventional additives that often offer limited or selective regulation, this work proposes a molecular‐configuration modulation approach using glutamine derivatives as a model system to cooperatively engineer the IHP and OHP. Among them, Glycyl‐L‐glutamine (Gly‐L‐Glu) exhibits an optimal configuration that promotes a vertically aligned adsorption geometry on the Zn surface. This specific orientation facilitates formation of a compact and ordered interfacial layer within IHP for effectively shielding the electrode from water‐induced side reactions, while simultaneously extends to reconstruct the OHP to optimize the interfacial solvation environment and accelerate desolvation kinetics. The resulting well‐defined electrode/electrolyte interphase fosters efficient charge transfer, and the presence of abundant electronegative zincophilic sites enhances ion transport and homogenizes Zn 2 + flux during deposition. Consequently, the Gly‐L‐Glu–modified electrolyte enables exceptional cycling stability of Zn anodes, achieving 7875 h at 1 mA cm −2 and nearly 4500 h at 5 mA cm −2 with 5 mAh cm −2 in Zn//Zn symmetric cells, an average Coulombic efficiency of 99.8% in Zn//Cu asymmetric cells. This work underscores the critical role of molecular configuration in additive design for advanced Zn metal anodes.