Elevating Discharge Voltage of Li₂CO₃-routine Li-CO₂Battery over 2.9 V at an Ultra-wide Temperature Window.

Abstract

The Li-CO₂ batteries utilizing greenhouse gas CO₂ possess advantages of high energy density and environmental friendliness. However, these batteries following Li₂CO₃-product route typically exhibit low work voltage (<2.5 V) and energy efficiency. Herein, we have demonstrated for the first time that cobalt phthalocyanine (CoPc) as homogeneous catalyst can elevate the work plateau towards 2.98 V, which is higher than its theoretical discharge voltage without changing the Li₂CO₃-product route. This unprecedented discharge voltage is illustrated by mass spectrum and electrochemical analyses that CoPc has powerful adsorption capability with CO₂(-7.484 kJ/mol) and forms discharge intermediate of C₃₃H₁₆CoN₈O₂. Besides high discharge capacity of 18724 mAh/g and robust cyclability over 1600 hours (1000 mAh/gcut-off) at a current density of 100 mA/g, the batteries show high temperature adaptability (-30~80 ⁰C). Our work is paving a promising avenue for the progress of high-efficiency Li-CO₂ batteries.