Abstract Two-dimensional MnO_x nanomembranes prepared by electron beam evaporation are rolled up into three-dimensional hybrid micro/nano-tubes by strain release. The material is characterized with Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), cyclic voltammetry and used as the cathode catalysts for lithium-oxygen (Li-O₂) batteries. The Li-O₂ battery using such curly MnO_x nanomembranes as the cathode delivers a specific discharge capacity of 4610 mAhgC-1 at a current density of 70 mAgC-1 which is higher than that of carbon black. Moreover, the MnO_x nanomembrane electrode gains improved stability, being capable of cycling 112 times at a current density of 200 mAgC-1. The encouraging performance is ascribed to the unique superiorities of nanomembranes and those inner oxygen vacancies, indicating that nanomembranes are promising materials for Li-O₂ batteries.