Effects of ultrasound on synthesis and performance of manganese-based/ graphene oxide oxygen reduction catalysts for aluminum-air batteries

In this research, manganese (Mn) based/graphene oxide (GO) composites, which are used as cathode catalysts for aluminum(Al)-air battery are successfully prepared via ultrasound method using KMnO₄–MnSO₄-GO system. The effects of ultrasonic amplitude on the synthesis and performance of catalysts are both investigated. The result reveals that changing the ultrasonic amplitude (10, 15 μm and 20 μm) is able to effectively affect the composition of catalysts, and which further influence their electrocatalytic and discharging performance. The catalyst obtained under an ultrasonic amplitude of 15 μm is composed of γ-manganese oxyhydroxide (γ-MnO(OH)), α-manganese dioxide (α-MnO₂) and GO, which has good electrocatalytic performance closing to a commercial 20% Platinum (Pt)/Carbon (C) catalyst. This research proposes a novel and efficient method by using ultrasound to prepare Mn based/GO catalysts with excellent electrocatalytic performance, which exhibit great potential in the field of metal-air battaries.