Tailoring the Discharge Reaction in Li-CO[subscript 2] Batteries through Incorporation of CO[subscript 2] Capture Chemistry

Abstract

The search for viable end-uses of CO₂ has motivated considerable research into CO₂ utilization in energy storage devices such as alkali metal-based O₂/CO₂ and -CO₂ batteries. However, efforts have been stymied by the low electrochemical activity of CO₂ in most organic media. In this work, we report a mediated CO₂ capture and conversion process, based on amine (e.g., 2-ethoxyethylamine) chemisorption, which provides a new electrolyte system for facilitating the discharge reaction in Li-CO₂ batteries. Our results indicate that electrochemical reduction of CO₂-loaded amines proceeds at significantly higher discharge potentials (∼2.9 V versus Li/Li+) compared with physically dissolved CO₂, which is inactive in the amine's absence. The discharge reaction forms solid-phase Li₂CO₃ as the primary discharge product and yields high discharge capacities (>1,000 mAh/gc), highlighting the coupling of CO₂ capture chemistry to nonaqueous batteries as a promising approach for the design and manipulation of CO₂ conversion reactions. Keywords: carbon dioxide; CO₂; CO₂ capture; CO₂ conversion; amine; Li-CO₂ battery; electrochemical reduction; ethoxyethylamine; Li₂CO₃