Elevating Discharge Voltage of Li2CO3-Routine Li-CO2 Battery 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-1) and forms discharge intermediate of C33H16CoN8O2. Besides high discharge capacity of 18724 mAh g-1 and robust cyclability over 1600 hours (1000 mAh g-1 cut-off) at a current density of 100 mA g-1, the batteries show high temperature adaptability (-30-80 °C). Our work is paving a promising avenue for the progress of high-efficiency Li-CO2 batteries.