Hydrothermal synthesis of LiNi0.5Mn1.5O4 sphere and its performance as high-voltage cathode material for lithium ion batteries

The LiNi0.5Mn1.5O4 spheres are prepared via hydrothermal route followed by high-temperature lithiation. The morphology of the Ni0.25Mn0.75CO3 precursor is optimized by adjusting the temperature and metal concentrations during the hydrothermal reaction. The results indicate that the sphere structure is easy to obtain while its size is tunable, especially in different hydrothermal temperatures. After lithiation, the prepared samples are indexed with pure-phase spinel LiNi0.5Mn1.5O4 and the elemental distribution shows no segregation. As used as high-voltage cathode material for lithium ion batteries, the prepared material shows considerable cycle performance, possessing 126 mAh g−1 at 0.1C in the voltage range of 3.0–4.95 V, and maintaining 71% capacity retention. The sample also exhibits good rate capability, delivering 58 mAh g−1 at 5C.