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Acting as a passive protective layer, solid‐electrolyte interphase (SEI) plays a crucial role in maintaining the stability of the Li‐metal anode. Derived from the reductive decomposition of electrolytes (e.g. anion and solvent), the SEI construction presents as an interfacial process accompanied by the dynamic de‐solvation process during Li‐metal plating. However, typical electrolyte engineering and related SEI modification strategies always ignore the dynamic evolution of electrolyte configuration at the Li/electrolyte interface, which essentially determines the SEI architecture. Herein, by employing advanced electrochemical in situ FT‐IR and MRI technologies, we directly visualize the dynamic variations of solvation environments involving Li+‐solvent/anion. Remarkably, a weakened Li+‐solvent interaction and anion‐lean interfacial electrolyte configuration have been synchronously revealed, which is difficult for the fabrication of anion‐derived SEI layer. Moreover, as a simple electrochemical regulation strategy, pulse protocol was introduced to effectively restore the interfacial anion concentration, resulting in an enhanced LiF‐rich SEI layer and improved Li‐metal plating/stripping reversibility. [ABSTRACT FROM AUTHOR]

Aqueous ammonium ion battery is a promising sustainable energy storage system. However, the side reactions originating from electrolytes (the water decomposition and host material dissolution) preclude its practical applications. Unlike the metal‐based aqueous batteries, the idea of "ultrahigh concentrated electrolyte" is not feasible due to the strong hydrolysis of ammonium ions. Therefore, we propose an effective and sustainable strategy for the water hydrogen bond network modulation by adding sucrose into the electrolytes. The sucrose can form sucrose‐water hydrogen bond networks to break the continuous water hydrogen bond network, thereby inhibiting water decomposition significantly. Moreover, the weak hydrogen bond interaction between ammonium and sucrose facilitates rapid ion migration, leading to an improved ionic conductivity. This work presents a new electrolyte modulating strategy for the practical application of aqueous ammonium ion batteries. [ABSTRACT FROM AUTHOR]