Mo2N-ZrO2 Heterostructure Engineering in Freestanding Carbon Nanofibers for Upgrading Cycling Stability and Energy Efficiency of Li-CO2 Batteries

Li-CO2 batteries have attracted considerable attention for their advantages of CO2 fixation and high energy density. However, the sluggish dynamics of CO2 reduction/evolution reactions restrict the practical application of Li-CO2 batteries. Herein, a dual-functional Mo2N-ZrO2 heterostructure engineering in conductive freestanding carbon nanofibers (Mo2N-ZrO2@NCNF) is reported. The integration of Mo2N-ZrO2 heterostructure in porous carbons provides the opportunity to simultaneously accelerate electron transport, boost CO2 conversion, and stabilize intermediate discharge product Li2C2O4. Benefiting from the synchronous advantages, the Mo2N-ZrO2@NCNF catalyst endows the Li-CO2 batteries with excellent cycle stability, good rate capability, and high energy efficiency even under high current densities. The designed cathodes exhibit an ultrahigh energy efficiency of 89.8% and a low charging voltage below 3.3 V with a potential gap of 0.32 V. Remarkably, stable operation over 400 cycles can be achieved even at high current densities of 50 mu A cm(-2). This work provides valuable guidance for developing multifunctional heterostructured catalysts to upgrade longevity and energy efficiency of Li-CO2 batteries.

Automated summary

A dual-functional Mo2N-ZrO2 heterostructure engineering in conductive freestanding carbon nanofibers (Mo2N-ZrO2@NCNF) is reported to enhance the performance of Li-CO2 batteries. The integration of Mo2N-ZrO2 heterostructure in porous carbons improves electron transport, CO2 conversion, and stabilizes discharge products. The designed cathodes show superior cycle stability, rate capability, and energy efficiency, even at high current densities, leading to an ultrahigh energy efficiency of 89.8% and stable operation over 400 cycles at 50 μA cm(-2). This work provides valuable guidance for developing multifunctional heterostructured catalysts to improve the longevity and energy efficiency of Li-CO2 batteries.