Reduced Graphene Oxide-Polypyrrole Composite as a Catalyst for Oxygen Electrode of High Rate Rechargeable Li-O₂Cells

Abstract

Polypyrrole (PPY) is grown on reduced graphene oxide (RGO) and the composite is studied as a catalyst for O2 electrode in Li-O2 cells. PPY is uniformly distributed on the two dimensional RGO layers. Li-O2 cells assembled in a non-aqueous electrolyte using RGO-PPY catalyst exhibit an initial discharge capacity as high as 3358 mAh g−1 (3.94 mAh cm−2) at a current density of 0.3 mA cm−2. The voltage gap between the charge and discharge curves is less for Li-O2(RGO-PPY) cell in comparison with Li-O2(RGO) cell. The Li-O2(RGO-PPY) cell delivers a discharge capacity of 550 mAh g−1 (0.43 mAh cm−2) at a current density of 1.0 mA cm−2. The results suggest that RGO-PPY is a promising catalyst of O2 electrode for high rate rechargeable Li-O2 cells.