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

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. Constructing the Fe/Fe3C heterostructure on carbon-based catalyst aims to achieve long-term performance of Li-CO2 batteries for reducing polarization voltage. The discharge product as the amorphous form endowed by designed heterostructure contributes to high cyclic stability and upper energy efficiency of the battery. The proposed strategy provides a new insight to design efficient carbon-based catalyst for practical applications. [Display omitted] •A low cost efficient catalyst is developed.•Heterostructure facilitate the well regulation of the discharge product.•Amorphous discharged product contributes to a low polarization voltage to 0.90 V.