A Wide-Temperature-Range Electrolyte for all Vanadium Flow Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• All-vanadium flow batteries (VFBs) offer scalable, long-duration energy storage.
• VFB performance is limited by vanadium electrolyte instability at extreme temperatures (-5°C to 45°C).
• Precipitation in electrolytes restricts VFB geographical adaptability.

Purpose of the Study:

• To develop a wide-temperature-range (WTR) electrolyte for VFBs.
• To overcome the thermal stability limitations of conventional vanadium electrolytes.
• To enhance the operational temperature window of VFBs.

Main Methods:

• Introduced four additives (benzene sulfonate, phosphate salts, halide salts, imidazole) into a conventional vanadium electrolyte.
• Conducted electrochemical characterization to assess performance.
• Tested electrolyte stability and operational capability across a wide temperature range (-5°C to 45°C).

Main Results:

• The WTR electrolyte demonstrated stable operation and storage between -5°C and 45°C.
• Electrochemical performance at 100 mA cm⁻² was comparable to conventional electrolytes.
• No performance sacrifice was observed with the WTR electrolyte.

Conclusions:

• A viable strategy for designing WTR vanadium electrolytes was established.
• The WTR electrolyte significantly expands the operational temperature range of VFBs.
• This research provides critical insights for deploying VFBs in diverse climatic environments.