<p>Aqueous zinc batteries (AZBs) are promising for sustainable energy storage due to their safety and affordability. Conventional ‘lean-water’ electrolytes improve cell cyclability and the electrochemical stability window by stabilizing the interface; however, ionic transport in the bulk is limited and the use of high-concentration salt jeopardizes their practical adaptability. Here we report a dual-salt electrolyte involving ZnSO₄ and Zn(ClO₄)₂ that decouples the interfacial chemistry from the bulk. Specifically, SO₄²⁻ ions populate the Zn/electrolyte interface, whereas ClO₄⁻ anions dominate in the bulk. Strongly hydrated SO₄²⁻ stabilizes interfacial water, while weakly hydrated ClO₄⁻ disrupts bulk hydrogen-bond networks, suppressing electrolyte freezing and enabling fast Zn²⁺ transport. In the absence of high salt concentrations and organic solvents, our decoupled electrolyte achieves a high ionic conductivity of 15.1 mS cm⁻¹ and Zn plating/stripping reversibility of 99.97% at −40 °C. Assembled Zn//NaV₃O₈ pouch cells under practical configurations show a daily self-discharge rate of 0.13%, retain 93% capacity after 900 cycles at 25 °C, and deliver full capacity retention over 3,000 cycles at −40 °C. This decoupled dual-salt electrolyte advances the practical deployment of AZBs and offers a strategy for rational and sustainable electrolyte design beyond aqueous systems.</p>