Rechargeable Hydrogen-Chlorine Battery Operates in a Wide Temperature Range

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Hydrogen-chlorine (H₂-Cl₂) fuel cells offer fast kinetics but face challenges in cost, efficiency, and reversibility.
• Rechargeable H₂-Cl₂ batteries are desirable for energy storage but technically difficult to develop.
• Existing aqueous chlorine batteries struggle with performance at low temperatures.

Purpose of the Study:

• To develop a rechargeable H₂-Cl₂ battery with a wide operating temperature range.
• To enhance the reversibility and stability of H₂-Cl₂ batteries.
• To enable energy storage solutions for extreme environments.

Main Methods:

• Designed a hierarchically porous carbon cathode for effective Cl₂ gas confinement and Cl₂/Cl^- redox activation.
• Utilized a phosphoric acid-based antifreezing electrolyte for low-temperature operation.
• Tested battery performance across a wide temperature range (-70 to 40 °C) including cycling stability and capacity.

Main Results:

• Achieved a rechargeable H₂-Cl₂ battery operating statically from -70 to 40 °C.
• Demonstrated a room-temperature discharge plateau at ~1.15 V with over 500 cycles without capacity decay.
• Observed a reversible discharge capacity of 282 mAh g^-1 at -70 °C and 91% average Coulombic efficiency for over 300 cycles at -40 °C.

Conclusions:

• The developed H₂-Cl₂ battery shows significant promise for reliable energy storage in wide temperature ranges.
• The hierarchically porous carbon cathode and antifreezing electrolyte are key to achieving enhanced reversibility and low-temperature performance.
• This work presents a viable strategy for advancing aqueous chlorine batteries for demanding energy storage applications.