High-Performance Salt-Lake Water Zinc Batteries Operated at −50 °C

Abstract

Low-temperature aqueous batteries are severely hindered by electrolyte freezing and a sharp drop in ionic conductivity at subzero temperatures, creating a fundamental trade-off between freeze resistance and rapid ion transport. Herein, we show that salt-lake (SL) water, an intrinsically abundant, low-cost, and naturally high-salinity medium, can directly replace deionized water as the electrolyte solvent for aqueous zinc (Zn)-ion batteries (AZIBs), offering high ionic conductivity and a low freezing point without energy-intensive purification. The high salinity of SL water in electrolytes effectively suppresses ice formation, maintains interfacial contact, and minimizes voltage loss. By reducing water coordination to Zn2+ ions, suppressing water activity, disrupting the hydrogen-bond network, and designing an artificial ternary alloy layer-coated Zn anode to enhance cation adsorption and electrostatic shielding, we achieve stable low-temperature AZIBs using SLPGCl electrolytes operated at −50 °C. The alloy layer-coated Zn symmetric cell in SLPGCl electrolyte delivers ultrastable cycling for over 3200 h at −50 °C. A full cell with a polyaniline cathode delivers over 2500 cycles at 5 A g–1, and the related pouch cell operates with long-term stability even after 900 cycles at −50 °C. This work provides a low-cost, geographically adaptable, and industrially scalable strategy for aqueous batteries operating under extreme cold conditions.