An Organic Acid-Alkali Coregulated Ionic Liquid Electrolyte Enabling Wide-Temperature-Range Proton Battery

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Rechargeable batteries are crucial for energy storage, but current technologies face limitations in sustainability, capacity, and operating temperature.
• Aqueous proton batteries offer safety and cost benefits but are hindered by narrow electrochemical stability and low boiling points of aqueous electrolytes.
• Developing wide-temperature operable, high-energy density batteries is essential for broad applications.

Purpose of the Study:

• To engineer a novel hybrid organic ionic liquid electrolyte for enhanced aqueous proton battery performance.
• To overcome the limitations of conventional aqueous electrolytes regarding temperature stability and electrochemical window.
• To demonstrate a high-performance proton battery utilizing the developed electrolyte for wide-temperature applications.

Main Methods:

• Synthesized a hybrid electrolyte (HTFSI-MTA-TMS) using organic alkali 1-methyl-1,2,4-triazole (MTA) and organic acid bis(trifluoromethysulfonyl)imide (HTFSI) in tetramethylene sulfone (TMS) solvent.
• Investigated the electrochemical stability window of the HTFSI-MTA-TMS electrolyte at various temperatures (-20°C to 80°C).
• Assembled and tested a MnO2-S//MoO3 proton full battery with the novel electrolyte, incorporating Mn(TFSI)2 salt.

Main Results:

• The HTFSI-MTA-TMS electrolyte demonstrated a wide electrochemical stability window, exceeding 5 V at -20°C and 3.5 V at 80°C.
• The assembled proton battery achieved an operating voltage of 1.8 V and an energy density of 44.8 Wh kg⁻¹.
• The battery exhibited good cycling stability at room temperature and operated effectively within a wide temperature range (-20°C to 60°C).

Conclusions:

• Organic acid-alkali coregulated electrolytes show significant potential for wide-temperature energy storage solutions.
• The developed hybrid electrolyte addresses key limitations of aqueous electrolytes, paving the way for high-energy proton batteries.
• This research advances the development of robust and efficient energy storage devices for demanding environmental conditions.