In the present work nanostructures of manganese dioxide have been synthesized and characterized as potential catalysts for Li-air batteries. The R-MnO2 nanourchin-shaped catalyst was synthesized by mild hydrothermal conditions under autogeneous pressure. X-ray powder diffraction (XRD) was used to confirm the formation of single R-MnO2. The microstructure of the obtained nanostructures was investigated by scanning and transmission electron microscopy (SEM and TEM) showing the presence of acicular manganese oxide aggregates (5-10 nm wide) which tend to form spherical clusters, taking on an urchin-shaped form of roughly 6 microns diameter. The cyclability analyses reveal an enhanced performance and efficiency for the batteries with higher amounts of catalyst. This catalyst is thought to promote alternative reaction pathways in the Li2CO3 decomposition which attenuate the instability of the electrolyte and/or carbon electrode during the discharge resulting in an improved cyclability.