An Efficient Oxygen Evolution Catalyst for Hybrid Lithium Air Batteries: Almond Stick Type Composite of Perovskite and Cobalt Oxide

Abstract

We investigated the electrochemical composite effect between cobalt oxide and Nd0.5Sr0.5CoO3-delta (Co-NSC). Adouble phase Co-NSC composite was successfully synthesized by a new synthesis process rather than a single phase Nd0.5Sr0.5Co1.1O3-delta perovskite. The composite has good catalytic activity, high number of transferred electrons (3.9) compatible with Pt/C, and low concentration of the peroxide species (HO2-) yields (< 5%). Also, it shows the outperformed onset potential (0.576 V vs. Hg/HgO) of the oxygen evolution reaction (OER) at -2.0mA cm(-2), indicating higher current density than perovskite related catalysts such as Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF), La1.7Sr0.3NiO4 (LSN), LaNiO3 (LNO) and the state-of-the-art rutile IrO2. The good catalytic activity of Co-NSC is ascribed to the higher amount of Co3+ cations and higher O-ad/O-lattice ratio. Interestingly, the cyclic performance of the composite is also remarkably stable without observable degradation in a hybrid lithium air cell.