To　date,　research　on　air　battery　catalysts　has　been　mainly　focused　on　finding　materials　with　a　high　oxygen　reduction　reaction　(ORR)　catalytic　activity.　However,　the　high　cost　of　platinum　catalysts　restricts　their　commercialization.　Herein,　we　report　a　simple　hydrothermal-calcination　method　to　fabricate　low-cost　NiMn2O4　-based　Ni-Mn　bimetallic　oxides.　The　Ni-Mn-600　sample　showed　a　high　onset　potential　(1.01　V　vs.　RHE),　which　was　more　positive　than　that　for　20　wt%　Pt/C　(0.97　V　vs.　RHE),　and　its　half-wave　potential　(0.78　V　vs.　RHE)　was　comparable　to　that　for　20　wt%　Pt/C　(0.84　V　vs.　RHE).　Moreover,　Ni-Mn-600　as　an　Al-air　battery　air–cathode　catalyst　exhibited　a　high　discharge　plateau　of　1.42　V　and　peak　power　density　of　100.45　mW　cm−2,　which　outperformed　those　for　20　wt%　Pt/C　(1.34　V　and　76.10　mW　cm−2).　The　high　ORR　electrocatalytic　activity　of　Ni-Mn-600　may　be　attributed　to　the　nanorod　morphology　and　high　ratio　of　(Mn3++Mn4+)/Mn2+　and　Ni3+/Ni2+.　This　work　demonstrated　that　NiMn2O4-based　Ni-Mn　bimetallic　oxides　as　cathode　catalysts　have　good　research　prospects　in　aluminum-air　batteries　and　other　energy　applications.　©　2020　Elsevier　B.V.