Highly crystalline spinel LiMn2O4 was successfully synthesized by annealing lithiated MnO2 at a relative low temperature of 600°C, in which the lithiated MnO2 was prepared by chemical lithiation of the electrolytic manganese dioxide (EMD) and LiI. The LiI/MnO2 ratio and the annealing temperature were optimized to obtain the pure phase LiMn2O4. With the LiI/MnO2 molar ratio of 0.75, and annealing temperature of 600°C, the resulting compounds showed a high initial discharge capacity of 127mAhg−1 at a current rate of 40mAhg−1. Moreover, it exhibited excellent cycling and high rate capability, maintaining 90% of its initial capacity after 100 charge–discharge cycles, at a discharge rate of 5C, it kept more than 85% of the reversible capacity compared with that of 0.1C.