Developing batteries that can function reliably in extremely cold environments is critical for various applications, such as powering devices, vehicles, and robotic systems in outer space and deep under the sea. To ensure safe and effective operation in such harsh conditions, it’s essential to design batteries with components that resist freezing and adverse reactions to temperature drops.
A recent study by researchers at the Chinese Academy of Sciences and other Chinese institutes proposes a new strategy for designing anti-freezing electrolytes for aqueous batteries. Published in Nature Energy, their approach focuses on two temperature-related factors—thermodynamic eutectic temperature (Te) and kinetic glass-transition temperature (Tg)—which have been overlooked in previous anti-freezing electrolyte designs.
While previous efforts mainly targeted regulating the freezing point (Tf), the exact temperature at which a liquid solidifies, this study suggests that Te and Tg may be more critical in determining battery performance at low temperatures. Te represents the lowest stable temperature of a solution under specific pressure, while Tg indicates the onset of molecular mobility and the transition to a rigid, glassy phase as the temperature decreases.
The researchers propose a general strategy for achieving low-Te and strong super-cooling ability electrolytes by creating multiple-solute systems with assisted salts containing high ionic-potential cations or cosolvents with high donor numbers. Demonstrating their approach with Na-based systems, they achieved electrolytes with ultralow Te and Tg, enabling battery performance even at extremely low temperatures.
This study provides a comprehensive guideline for designing anti-freezing electrolytes, which could advance the development of batteries for space, deep-sea, and other extreme environments. By focusing on Te and Tg, researchers may unlock new possibilities for improving battery solutions in challenging conditions.
