Substituting mechanical stirring by ultrasonic irradiation in co-precipitation method, cathode material LiNi 0.5 Mn 0.5 O 2 for lithium batteries with better layered structure and crystallinity has been successfully synthesized. The physicochemical and electrochemical properties of ultrasonic co-precipitation (UCP) prepared material were compared with those of the mechanical stirring co-precipitation (MSCP) prepared material by thermogravimetery analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), and galvanostatic charge–discharge testing in detail. UCP prepared LiNi 0.5 Mn 0.5 O 2 presents better rate discharge capability, cyclic stability and reversibility, resulting from smaller electrochemical polarization during electrode reaction and easier lithium ion insertion/desertion. Application of ultrasonic irradiation during the co-precipitation preparation process is beneficial to produce samples with better physicochemical and electrochemical properties.