Binuclear Cu complex catalysis enabling Li–CO 2 battery with a high discharge voltage above 3.0 V

Li–CO 2 batteries possess exceptional advantages in using greenhouse gases to provide electrical energy. However, these batteries following Li 2 CO 3 -product route usually deliver low output voltage (<2.5 V) and energy efficiency. Besides, Li 2 CO 3 -related parasitic reactions can further degrade battery performance. Herein, we introduce a soluble binuclear copper(I) complex as the liquid catalyst to achieve Li 2 C 2 O 4 products in Li–CO 2 batteries. The Li–CO 2 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 −1 . 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 2 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 2 batteries to higher than 3.0 V, paving a promising avenue for the design and regulation of CO 2 conversion reactions.