A Theory-Driven Moderation Strategy for Electrolyte Design Unlocks Stable Aqueous Zinc Deposition.

Abstract

How theoretically screened solvation characteristics of additives affect zinc deposition behavior has emerged as a critical question of both scientific and practical relevance. Here, using a series of structurally analogous alcohol-based molecules as a model system and guided by theoretical calculations, we establish a non-extremum empirical model for additive screening to balance the relationship between additive theoretically properties and the solvation/interface stability in aqueous Zn-ion battery electrolytes. Solvation capability, adsorption strength, and interfacial electrostatic properties were calculated to directly probe the critical role of a balanced set of molecular parameters in modulating Zn2+ coordination structure and interface stability. As a result, 1,6-hexanediol, exhibited a set of balanced and non-extremum molecular parameters, significantly enhanced the reversibility of zinc deposition/stripping, delivered the best electrochemical performance that extending the cycling lifespan to 2 600 h, which is consistent with the Sabatier principle. This study provides a new theoretical perspective for the rational screen of electrolyte additives and highlights the importance of expanding the selection criteria for optimizing interfacial stability.