• Introduction of low-cost Na+ into Zn(ClO4)2 electrolyte suppresses Zn2+ aggregation via preferential adsorption and electrostatic repulsion, enabling homogeneous Zn deposition and enhanced low-temperature reversibility.
• Na+ with low ionic potential spontaneously adsorbs at the anode–electrolyte interface, reducing solvated water molecules and suppressing parasitic reactions, significantly improving Coulombic efficiency at low temperatures.
• At −40 °C, Zn||Zn cells maintained stable cycling for over 2500 h, and Zn||PANI full cells exhibited over 8000 cycles with >90% capacity retention.
• The organic-free antifreeze electrolyte offers a cost-effective and practical strategy for long-term operational stability of aqueous zinc metal batteries in subzero environments.