Preparation of LiNi0.5Mn1.5O4 cathode materials by using different-sized Mn3O4 nanocrystals as precursors

High-voltage LiNi 0.5 Mn 1.5 O 4 with a spinel structure is considered as important cathode materials for high-energy density Li-ion batteries (LIBs). In this study, we investigate the size, structure, and the electrochemical performance of LiNi 0.5 Mn 1.5 O 4 electrodes prepared by using two different-sized Mn 3 O 4 nanocrystal precursors under different calcination conditions. As the calcination temperature rises, the particle sizes of the acquired LiNi 0.5 Mn 1.5 O 4 cathode materials can vary from ~ 100 nm to ~ 1 µm, and the morphology changes from nano round shape to truncated octahedral shape. The content of Mn 3+ is closely related to the calcination temperature and is affected by the size of Mn precursor. It is found that the LiNi 0.5 Mn 1.5 O 4 sample prepared by using 50-nm-sized Mn 3 O 4 nanocrystals under a calcination temperature of 800 C exhibits good cycling performance with a capacity retention ratio of 96.1% at 1 C after 200 cycles, while the LiNi 0.5 Mn 1.5 O 4 sample prepared by using 7-nm-sized Mn 3 O 4 nanocrystals under a calcination temperature of 800 °C shows an excellent rate performance with a capacity retention ratio of 98% after 500 cycles at 10 C. The results show that the size of Mn 3 O 4 precursor is an important parameter that governs the final size and electrochemical performances of LiNi 0.5 Mn 1.5 O 4 cathode materials.