Manipulating coordination environment for a high-voltage aqueous copper-chlorine battery

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous copper-based batteries offer advantages but are limited by low operating voltage due to the high redox potential of copper electrodes.
• The intrinsic negative electrode potential of 0.34 V vs. SHE restricts the overall voltage and energy density of these systems.

Purpose of the Study:

• To reduce the intrinsic negative electrode redox potential in aqueous copper-based batteries through electrolyte modification.
• To enhance the operating voltage and energy storage capabilities of aqueous copper batteries.

Main Methods:

• Electrolyte tailoring using chloride (Cl-) ions to create a specific coordination environment for copper ions.
• Stabilization of intermediate Cu+ ions and decoupling of the electrochemical process into distinct Cu2+/Cu+ and Cu+/Cu0 redox reactions.
• Development and testing of an aqueous copper-chlorine battery utilizing the Cl-/Cl0 redox couple.

Main Results:

• Coordination with Cl- ions lowered the Cu+/Cu0 redox potential by approximately 0.3 V compared to water coordination.
• The copper-chlorine battery achieved a high discharge voltage of 1.3 V.
• The battery demonstrated superior cycle stability, retaining 77.4% of its initial capacity after 10,000 cycles, with improved copper utilization and redox kinetics.

Conclusions:

• Electrolyte engineering via Cl- ion coordination is an effective strategy to decrease copper electrode potential and boost aqueous battery voltage.
• The developed aqueous copper-chlorine battery shows promise for high-performance energy storage applications.
• This approach opens new avenues for developing high-voltage and high-energy aqueous copper batteries.