Chloride Regulated CuxO/RuCu Heterostructure Electrocatalyst towards High-Performance Li-CO2 Battery

Abstract

Lithium-carbon dioxide (Li-CO2) battery has attracted extensive attention since it provides a distinctive approach to mitigate the CO2 accumulation and simultaneously deliver high energy density electricity. However, the abnormally high voltage is usually applied to decompose the lithium carbonate (Li2CO3) discharge products in reversible charge direction, which thus leads to low energy efficiency and poor reversibility, seriously hindering the advance of Li-CO2 battery. Herein, one novel chloride regulated CuxO/RuCu heterostructure (CuxO-Cl/RuCu) electrocatalyst is designed and prepared for largely reducing the decomposition barrier of Li2CO3 in Li-CO2 battery. The CuxO-Cl/RuCu is characterized by porous octahedral microstructure with numerous Cuδ+/Cu0 heterointerfaces modified by both the non-metallic Cl and metallic Ru. The CuxO-Cl/RuCu electrocatalyst with downshifted d-band center thus exhibits boosted electrocatalytic decomposition ability towards Li2CO3. The Li-CO2 battery with CuxO-Cl/RuCu displays large discharge capacity of 8041.73 μAh·cm-2, durable cycling performance of 180 cycles, and impressive rate capability at 200 μA·cm-2, outperforming the Cu2O counterpart. The diverse characterizations after charge-discharge periods and systematically theoretical calculation further confirm the superb electrocatalytic ability and durability of the CuxO-Cl/RuCu for Li2CO3 decomposition. Notably, these results offer new insights into previously unknown role of chloride residues and how to improve the Cu-based electrocatalyst for Li-CO2 battery.