“…Therefore, it is necessary to develop stable and efficient electrocatalysts with proper morphology for the oxygen reduction and oxygen evolution reactions in the lithium air battery 1 2 3 4 5 6 7 . The electrocatalysts can be roughly classified into the following three categories: (1) porous carbon materials, including carbon black, nanostructured carbon, functionalized carbon, and graphene, which, strictly speaking, are not electrocatalysts, but act as electrocatalyst support or as an electrically conductive additive 8 9 10 11 12 13 14 ; (2) precious metals (alloys), for example, Pt, Au, Ag, and Pd, which might make a lithium air battery economically impractical 15 16 17 18 19 ; and (3) transition metal oxides, mainly manganese-based oxides and composites, and cobalt oxides 9 20 21 22 23 24 , which have attracted great attention because of their potential low cost and rich resources. Among these catalysts, various structures and morphologies of manganese oxide, such as MnO 2 nanowires, MnO 2 hollow spheres, and MnO 2 nanorods, have been synthesized and used as cathode catalysts for lithium air batteries 20 .…”