CuMnO 2 Nanoflakes as Cathode Catalyst for Oxygen Reduction Reaction in Magnesium-Air Battery

Developing efficient and stable ORR catalysts for Mg-air batteries is crucial to enabling extensive applications. Herein, CuMnO 2 nanoflakes were synthesized with a facile one-step hydrothermal way and applied as the cathode catalyst for Mg-air batteries. The ORR activities in alkaline and neutral electrolyte were then investigated. The half-wave potential has a minus variation of 22 mV after 5000 cycles, indicating the outstanding stability of the CuMnO 2 . The electron transfer number of the CuMnO 2 is 3.70 under neutral condition, which demonstrates that the reaction process of ORR is equivalent to the commercial Pt catalyst. Moreover, the primary Mg-air battery with CuMnO 2 as the cathode catalyst was assembled and the discharge properties were tested. The open circuit voltage achieved was 1.78 V and the operating voltage remained about 1.36 V after 22 h operation at 1.0 mA·cm −2 . It is evident that the CuMnO 2 nanoflake is an effective catalyst to accelerate the reaction rate of ORR process in Mg-air battery. This work provides a novel approach for the subsequent exploration of non-noble metal catalysts for Mg-air batteries.