Fe-based hybrid electrocatalysts for nonaqueous lithium-oxygen batteries

Lithium–oxygen batteries promise high energy densities, but are confronted with challenges, such as high overpotentials and sudden death during discharge–charge cycling, because the oxygen electrode is covered with the insulating discharge product, Li(2)O(2). Here, we synthesized low–cost Fe–based nanocomposites via an electrical wire pulse process, as a hybrid electrocatalyst for the oxygen electrode of Li–O(2) batteries. Fe(3)O(4)-Fe nanohybrids–containing electrodes exhibited a high discharge capacity (13,890 mA h g(c) (−1) at a current density of 500 mA g(c) (−1)), long cycle stability (100 cycles at a current rate of 500 mA g(c) (−1) and fixed capacity regime of 1,000 mA h g(c) (−1)), and low overpotential (1.39 V at 40 cycles). This superior performance resulted from the good electrical conductivity of the Fe metal nanoparticles during discharge–charge cycling, which could enhance the oxygen reduction reaction and oxygen evolution reaction activities. We have demonstrated the increased electrical conductivity of the Fe(3)O(4)-Fe nanohybrids using electrochemical impedance spectroscopy.