Highly efficient Li-CO2 batteries with regulated discharge product enabled by a hetero-structured N-C/Fe3C/Fe cathodic catalyst

Abstract

Lithium carbon dioxide (Li-CO₂) batteries have been regarded as a promising technology to alleviate the greenhouse effect and meet the demands for high-energy applications. However, the sluggish CO₂ transformation kinetics and the Li₂CO₃-related parasitic reactions degrade the battery's performance. Herein, we introduce a heterostructure N-doped carbon combined Fe₃C/Fe as a low-cost catalyst to regulate the formation of discharged product and accelerate the CO₂ redox kinetics. Systematically experimental characterizations reveal that the as-designed heterostructure can control the discharge product as the amorphous form to reduce the polarization voltage, thereby improving the cycle stability and increasing the energy efficiency of the battery. As a result, the assembled Li-CO₂ batteries exhibit a high full discharge capacity of 16550 mAh g⁻¹ with an excellent initial Coulombic efficiency of 96.7 % and maintain a low overpotential of 1.42 V over 200 cycles at 300 mA g⁻¹. This work provides a new research insight to design high-efficient and low-cost Li-CO₂ batteries with small overpotential and long-lifespan.