Facile synthesis of Fe@Fe2O3 core-shell nanowires as O2 electrode for high-energy Li-O2 batteries

Abstract

Fe@Fe2O3 core-shell nanowires were synthesized via the reduction of Fe3+ ions by sodium borohydride in an aqueous solution with a subsequent heat treatment to form Fe2O3 shell and employed as a cathode catalyst for non aqueous Li-air batteries. The synthesized core-shell nanowires with an average diameter of 50–100 nm manifest superior catalytic activity for oxygen evolution reaction (OER) in Li-O2 batteries with the charge voltage plateau reduced to ∼3.8 V. An outstanding performance of cycling stability was also achieved with a cutoff specific capacity of 1000 milliampere hour per gram over 40 cycles at a current density of 100 mA g−1. The excellent electrochemical properties of Fe@Fe2O3 as an O2 electrode are ascribed to the high surface area of the nanowires’ structure and high electron conductivity. This study indicates that the resulting iron-containing nanostructures are promising catalyst in Li-O2 batteries.