The　declining　performance　of　aqueous　zinc　metal　batteries　(AZMBs)　at　colder　temperatures,　especially　due　to　aqueous　electrolyte　solidification　and　reduced　capacity　retention　at　subzero　temperatures,　poses　a　considerable　challenge.　Here,　we　report　a　cheap　and　ecofriendly　aqueous　electrolyte　formulation　comprising　low-concentration　zinc　chloride　salt　and　a　common　antifreeze　agent.　We　show　that　the　glycerin　antifreeze　co-solvent　effectively　interacts　with　free　water　molecules　and　weakens　the　zinc-ion　primary　solvation　structures,　thereby　considerably　mitigating　their　detrimental　effect　at　low　temperatures.　Consequently,　the　optimized　electrolyte　successfully　outputs　a　depressed　liquid-glass　transition　point　down　to　−99.2　°C　and　a　record-high　Zn　plating/stripping　Coulombic　efficiency　of　∼99.94%　at　−40　°C,　as　well　as　∼70%　of　its　room-temperature　capacity　at　−40　°C,　opening　up　a　new　opportunity　for　practical　AZMBs.　©　2025　American　Chemical　Society.