Chain Effect-controlled Solvation Chemistry and Interfacial Microstructure Enables Highly Reversible Zn Metal Anode

Abstract

The charge transfer kinetics of Zn plating/stripping and the parasitic reactions are affected by the adsorption of Zn²⁺ and the subsequent desolvation process proceeded at the electrode/electrolyte interface (EEI). Herein, this work cleverly utilizes the “chain effect” triggered by the L-Methionine (Met) molecules to improving the stability of EEI by the solvation chemistry and interfacial microstructure reconfiguration. Firstly, the introduction of Met molecules enhances the solvation ability of anions, which squeezes out solvated H₂O molecules and generate anion-derived hybrid solid electrolyte interphase (SEI) layer, weakening H₂O-induced parasitic reactions and expediting the migration rate of Zn²⁺ at EEI. Meanwhile, the strengthened anion-cation interaction quickens the desolvation kinetics of Zn²⁺, homogenizing Zn²⁺ flux at interface. Secondly, Met molecules with multiple active sites not only break the original H-bonds network between H₂O molecules, further reducing the reactivity of H₂O molecules, but also preferentially adsorb on the Zn₍₁₀₁₎ and Zn₍₁₁₀₎ crystal planes to increase the exposure of Zn₍₀₀₂₎ crystal face, improving the stability of SEI and inducing uniform Zn deposition. Consequently, the symmetric/asymmetric cell in the Met-containing electrolyte demonstrates a long cycling life over 2700 h and high reversibility up to 4500 cycles, respectively. And the assembled full cells and pouch-cell exhibit outstanding cycling performance.