High-power double-face flow Al-air battery enabled by CeO2 decorated MnOOH nanorods catalyst

Aluminum-air (Al-air) battery has been regarded as one of the most promising next-generation energy storage devices. Manganese oxides (MnOx) are widely studied as non-noble metal oxygen reduction reaction (ORR) electrocatalysts with low cost and high stability. However, they still possess inferior ORR activity for commercial applications. In this study, an architecture of CeO2 nanoparticles decorated MnOOH nanorods (MnOOH@CeO2) is prepared by a simple one-step solvothermal method as an ORR catalyst. Interestingly, the incorporation of CeO2 can significantly strengthen the ORR activities of MnOOH. The half-wave potential of MnOOH@CeO2 reaches 0.80 V vs. RHE, which shows a 30 mV positive shift compared with MnOOH. It has been verified that the significant improvement ORR activity of MnOOH@CeO2 is attributed to their synergistic effect of MnOOH and CeO2, resulting in much better oxygen activation, oxygen enrichment, and H2O2 inhibition. In a practical double face flow Al-air battery system, MnOOH@CeO2 catalyst even exhibits better electrocatalytic performance (the discharge voltage of 0.65 Vat 400 mA cm(-2), the higher energy density of 3595.4 Wh kgAl(-1) and power density of 302.8 mW cm(-2)) than the commercial 20% Pt/C, further highlighting the multi-functions of CeO2 nano particles attaches to MnOOH nanorods.