Efficiently catalyzed sea urchin-like mixed phase SmMn2O5/MnO2 for oxygen reduction reaction in zinc-air battery

In this work, sea urchin-like SmMn 2 O 5 /MnO 2 is synthesized by the hydrothermal method . Compared with SmMn 2 O 5 , SmMn 2 O 5 /MnO 2 has a half wave potential of 0.82 V (vs RHE), which shows excellent electrocatalytic activity of oxygen reduction reaction (ORR) in the alkaline media. More importantly, the composite of SmMn 2 O 5 /MnO 2 shows higher number of electron transfers , better stability of ORR, and stronger methanol-tolerant ability comparison with the commercial catalyst of Pt/C. The remarkable ORR activity is due to the formation of abundant oxygen vacancies and Mn 3+ , which are beneficial to the adsorption of oxygen species and the activation of O-O bond. The sea urchin-like morphology increases the specific surface area, and the tip-like synapses play an essential role in charge accumulation and rapid transfer. Moreover, the rechargeable zinc-air battery made of SmMn 2 O 5 /MnO 2 not only has a high peak power density, but also has excellent cycle stability of 450 h in long-term charge discharge measurement.