5 V cathode material LiNi0.5Mn1.5O4 was synthesized via an oxalate co-precipitation process. The synthesized product was characterized by XRD, SEM, charge/discharge test and cyclic voltammetry. XRD and SEM results indicate that the synthesized product LiNi0.5Mn1.5O4 has cubic spinel structure with space group of Fdˉ3 m, high crystallinity, moderate and uniform particle size. The electrochemical experiment results show that the LiNi0.5Mn1.5O4 has excellent performances. It has only one discharge plateau at around 4.7 V. 0.1 C discharge capacity is up to 133 mAh/g and retains above 128 mAh/g after 50 cycles, 1 C and 3 C discharge capacities after 30 cycles also retain above 122 mAh/g and 101 mAh/g, respectively