A simple one-step route using gas template method is applied to synthesize macroporous LiNi0.5Mn0.5O2 which is characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Telle (BET) surface area, charge–discharge tests and electrochemical impedance spectroscopy (EIS) measurements. The as-synthesized material shows pure crystalline phase of LiNi0.5Mn0.5O2, while the microstructure is comprised of macrospores ranging from 0.2 to 0.5μm. The first discharge capacity is of 174mAhg−1 at 0.1C rate, which is much higher than that of the material synthesized by the conventional solid state reaction method. Furthermore, the macroporous LiNi0.5Mn0.5O2 material shows remarkable rate capacity and cycle stability, which may be attributed to the shorter lithium ion diffusion distance and better electrolyte penetration.