Fe-based hybrid electrocatalysts for nonaqueous lithium-oxygen batteries.

ABSTRACT: 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, Li2O2. Here, we synthesized low-cost Fe-based nanocomposites via an electrical wire pulse process, as a hybrid electrocatalyst for the oxygen electrode of Li-O2 batteries. Fe3O4-Fe nanohybrids-containing electrodes exhibited a high discharge capacity (13,890?mA?h gc-1 at a current density of 500?mA gc-1), long cycle stability (100 cycles at a current rate of 500?mA gc-1 and fixed capacity regime of 1,000?mA?h gc-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 Fe3O4-Fe nanohybrids using electrochemical impedance spectroscopy.

SUBMITTER: Lee S 

PROVIDER: S-EPMC5573321 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature