Sub-micro spinel-structured LiMn1.5Ni0.5O4 material was prepared by a spray-drying method. The electrochemical properties of LiMn1.5Ni0.5O4 were investigated using Li ion model cells, Li/LiPF6 (EC+DMC)/LiMn1.5Ni0.5O4. It was found that the first reversible capacity was about 132mAhg−1 in the voltage range of 3.60–4.95V. Ex situ X-ray diffraction (XRD) analysis had been used to characterize the first charge/discharge process of the LiMn1.5Ni0.5O4 electrode. The result suggested that the material configuration maintained invariability. At room temperature, on cycling in high-voltage range (4.50–4.95V) and low-voltage range (3.60–4.50V), the discharge capacity of the material was about 100 and 25mAhg−1, respectively, and the spinel LiMn1.5Ni0.5O4 exhibited good cycle ability in both voltage ranges. However, at high temperature, the material showed different electrochemical characteristics. Excellent electrochemical performance and low material cost make this spinel compound an attractive cathode for advanced lithium ion batteries.