Binder‐Free MoN Nanofibers Catalysts for Flexible 2‐Electron Oxalate‐Based Li‐CO2 Batteries with High Energy Efficiency

Abstract Owing to the ultrahigh theoretical energy density and environmental friendliness of CO 2 fixation, Li‐CO 2 batteries are regarded as one of sustainable high‐energy‐density power sources for different applications including wearable electronics. Most of reported Li‐CO 2 batteries utilize expensive, noble metal‐based catalysts via 4‐electron Li 2 CO 3 as discharged products, leading to low energy efficiency, electrolyte side‐reaction, and sluggish reaction kinetics. Herein, a 2‐electron Li‐CO 2 battery based on noble metal‐free and binder‐free MoN nanofibers on carbon cloth is fabricated with high energy efficiency and fast reaction kinetics. The fabricated batteries exhibit an initial median charge potential of low to 3.19 V with a potential gap of 0.36 V, high energy efficiency up to 88%, and > 500 h cycle stability. Experimental and theoretical computation results demonstrate that Li 2 C 2 O 4 as 2‐electron intermediate products are stabilized by delocalized electrons of Mo 3+ in MoN to form the Mo–O coupling bridge, leading to reversible Li 2 C 2 O 4 formation/decomposition accompanied with high energy efficiency and fast battery reaction. The batteries also show superior flexibility and stable power output under different deformations.