Dual-solvent mediated solvation-to-interphase coupling enables durable wide-temperature aqueous zinc ion batteries.

Abstract

Dendrite growth, hydrogen evolution, and surface passivation are fundamentally governed by solvation chemistry and interfacial kinetics, particularly under wide temperature ranges. Herein, we develop a dual-solvent mediated solvation-to-interphase coupling strategy by introducing adiponitrile (ADN) and diethylene glycol dimethyl ether (DGM) as complementary co-solvents into a Zn(OTf)2 baseline electrolyte. DGM coordinates with Zn2+ through multiple ether oxygen sites and preferentially adsorbs at the Zn interface, while ADN enters the primary Zn2+ solvation sheath through terminal nitrile groups. The cooperation constructs an H2O-poor, anion-involved, and structurally heterogeneous solvation environment while disrupting the continuous hydrogen bond network among H2O molecules. Such a regulated solvation structure maintains sufficient bulk ion transport at low temperatures and suppresses interfacial side reactions at elevated temperatures. Meanwhile, preferential co-solvent adsorption, partial DGM decomposition and enhanced interfacial participation of ADN and OTf--related species create an H2O-deficient interface and an organic-inorganic hybrid solid electrolyte interphase thereby homogenizing Zn2+ flux and promoting compact Zn deposition with a preferred (002) texture. Consequently, Zn||Zn symmetric and Zn||Cu asymmetric cells employing the designed electrolyte demonstrate long cycling stability and high reversibility from -30 to 50 °C, while a Zn||PANI pouch cell maintains 90.9% capacity retention after 1600 cycles.