Highly Stable Spinel Oxide Cathode for Rechargeable Li-O2 Batteries in Non-Aqueous Liquid and Gel-Based Electrolytes

Metal-air batteries are receiving interest as they provide higher theoretical specific energy compared to the commercial lithium-ion batteries with two interacalation electrodes. In this, lithium-oxygen (Li-O-2) batteries are among the most promising candidates for the electrical vehicles because of their ability in holding the large amount of energy density by reacting with atmospheric air oxygen as the cathode reactant. The few problems that need to be overcome for the use of these batteries are capacity fading by the accumulation of discharge products (e.g., Li2O2) on the electrode and stagnant electrode reactions. Hence, here, we synthesized a lowcost bimetallic spinet oxide NiFe2O4 electrocatalyst via a simple modified hydrothermal method for Li-O-2 batteries as the cathode material in non-aqueous liquid and polymer gel electrolytes. The bifunctional NiFe2O4 catalyst exhibited a high discharge capacity, better cyclic stability (100 cycles at current densities up to 1500 mA g(-1) and constant capacities of 1000 and 500 mA h g(-1)) and low overpotential. The enhanced performance of the battery is due to the presence of the multivalent bimetallic Ni and Fe metals in the catalyst.