Aqueous Batteries Operated at -50 °C

Area of Science:

• Electrochemistry
• Materials Science
• Physical Chemistry

Background:

• Electrochemical energy storage faces challenges at low temperatures, primarily insufficient ionic conductivity and electrolyte freezing.
• Developing electrolytes that maintain performance in sub-zero conditions is crucial for expanding battery applications.

Purpose of the Study:

• To engineer a novel electrolyte with a significantly reduced freezing point for low-temperature electrochemical energy storage.
• To investigate the mechanism enabling stable electrolyte operation at ultra-low temperatures.

Main Methods:

• Formulation of a new electrolyte by adding dimethyl sulfoxide (DMSO) to an aqueous 2m NaClO4 solution.
• Characterization of ionic conductivity at low temperatures (-50°C).
• Spectroscopic investigations and molecular dynamics (MD) simulations to understand electrolyte behavior.

Main Results:

• The developed 2M-0.3 electrolyte (2m NaClO4 with 0.3 molar fraction DMSO) exhibited a freezing point below -130°C.
• Sufficient ionic conductivity (0.11 mS/cm) was achieved at -50°C.
• Stable hydrogen bonds between DMSO and water molecules were identified as key to low-temperature stability.

Conclusions:

• The DMSO-based electrolyte enables aqueous rechargeable alkali-ion batteries (AABs) to function effectively at -50°C.
• This study presents a simple and effective strategy for developing low-temperature AABs.
• The findings pave the way for reliable energy storage solutions in cold environments.