Binuclear Cu complex catalysis enabling Li-CO battery with a high discharge voltage above 3.0 V.

Li-CO batteries possess exceptional advantages in using greenhouse gases to provide electrical energy. However, these batteries following LiCO-product route usually deliver low output voltage (<2.5 V) and energy efficiency. Besides, LiCO-related parasitic reactions can further degrade battery performance. Herein, we introduce a soluble binuclear copper(I) complex as the liquid catalyst to achieve LiCO products in Li-CO batteries. The Li-CO battery using the copper(I) complex exhibits a high electromotive voltage up to 3.38 V, an increased output voltage of 3.04 V, and an enlarged discharge capacity of 5846 mAh g. And it shows robust cyclability over 400 cycles with additional help of Ru catalyst. We reveal that the copper(I) complex can easily capture CO to form a bridged Cu(II)-oxalate adduct. Subsequently reduction of the adduct occurs during discharge. This work innovatively increases the output voltage of Li-CO batteries to higher than 3.0 V, paving a promising avenue for the design and regulation of CO conversion reactions.