A Crystalline/Amorphous Cobalt(II,III) Oxide Hybrid Electrocatalyst for Lithium–Air Batteries

Weakening of the oxygen bond is the main intention in the design and synthesis of catalysts for the oxygen reduction reaction (ORR). Hybrid-structured electrocatalysts are promising candidates for this purpose; however, the use of noble metals and the combination of different materials, such as graphene and metal oxides, usually limits their synthesis on the laboratory scale. Herein, we introduce an oxidation and rapid-cooling process as a novel and facile way to synthesize a bare Co3O4 hybrid crystalline/amorphous catalyst. Characterization of this material shows that the facile synthesis process is effective in forming an amorphous layer on the crystal structure of Co3O4. The cyclic voltammetry and rotating disc electrode results in aqueous solution prove the good performance of the catalyst. A Li–air battery with this catalyst successfully sustains about 2500 h of continuous cycling (120 cycles) with an average discharge voltage of 2.80 V and a limited specific capacity of 1000 mAh g−1, which proves the high performance of this catalyst in non-aqueous electrolyte. We show that the origin of the high catalytic performance in this hybrid structure derives from the synergistic behavior of two different active sites, and this concept facilitates the design and synthesis of electrocatalysts by rapid-cooling synthesis for the industrial scale.