Low-Temperature and High-Rate Rechargeable Aluminum Batteries Enabled by Ternary Eutectic Electrolytes

Area of Science:

• Electrochemistry and Materials Science
• Energy Storage Systems

Background:

• Rechargeable aluminum batteries (RABs) are attractive due to aluminum's high capacity, low cost, and safety.
• Current RAB performance is limited by electrolytes with narrow operational voltage windows.

Purpose of the Study:

• To develop a novel ternary eutectic electrolyte for rechargeable aluminum batteries.
• To enhance the operational voltage window and low-temperature performance of RABs.

Main Methods:

• Formulation of a ternary eutectic electrolyte using [C2C1im]Cl, [C4C1im]Cl, and AlCl3.
• Electrochemical characterization of the electrolyte and Al||graphene nanoplatelets cells.
• Testing battery performance at various current densities and sub-zero temperatures.

Main Results:

• The electrolyte achieved a wide operational potential window (~3 V) and high ionic conductivity (~8.3 mS/cm).
• The Al||graphene nanoplatelets cell demonstrated high capacities (~117 mAh/g at 1 A/g) and retained capacity at -40°C.
• The electrolyte exhibited a low glass transition temperature (-65°C), suitable for all-climate operation.

Conclusions:

• The developed ternary eutectic electrolyte significantly improves RAB performance.
• This electrolyte offers a promising solution for high-performance, all-climate energy storage systems.
• The findings pave the way for advanced rechargeable aluminum battery technologies.