Efficient Rechargeable Li-CO₂ Battery with a Liquid Electrolyte-Soluble CuCl₂ Electrocatalyst.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Nonaqueous Lithium-Carbon Dioxide (Li-CO2) batteries offer high theoretical energy density but suffer from poor cyclability and high overpotentials.
• Efficient electrocatalysts are crucial for overcoming kinetic barriers in CO2 reduction and improving Li-CO2 battery performance.

Purpose of the Study:

• To investigate cupric chloride (CuCl2) as a novel, liquid electrolyte-soluble electrocatalyst for nonaqueous Li-CO2 batteries.
• To elucidate the mechanism of CuCl2-mediated electrocatalysis in Li-CO2 systems.

Main Methods:

• Electrochemical characterization of Li-CO2 cells with and without CuCl2 additive.
• Analysis of discharge products using techniques to identify intermediates and final products.
• Investigation of the redox couple of CuCl2 in relation to the Li-CO2 battery potential.

Main Results:

• Cupric chloride (CuCl2) significantly reduces the cell overpotential from ≈1.7 V to 0.65 V.
• CuCl2 facilitates efficient electrocatalysis of CO2 reduction on carbon nanotube-loaded cathodes.
• Lithium oxalate (Li2C2O4) was detected as an intermediate, a seldomly reported species in Li-CO2 battery discharge products.

Conclusions:

• Cupric chloride (CuCl2) is a promising and effective electrocatalyst for enhancing nonaqueous Li-CO2 battery performance.
• The study elucidates the electrocatalytic mediation of CuCl2, highlighting its role in improving reaction kinetics and potentially altering discharge product pathways.