Molten salt synthesis of LiNi0.5Mn1.5O4 spinel for 5 V class cathode material of Li-ion secondary battery

Well-ordered high crystalline LiNi_0.5Mn_1.5O₄ spinel has been readily synthesized by a molten salt method using a mixture of LiCl and LiOH salts. Synthetic variables on the synthesis of LiNi_0.5Mn_1.5O₄, such as synthetic atmosphere, LiCl salt amount, synthetic temperature, and synthetic time, were intensively investigated. X-ray diffraction (XRD) patterns and scanning electron microscopic (SEM) images showed that LiNi_0.5Mn_1.5O₄ synthesized at 900 and 950 °C have cubic spinel structure () with clear octahedral dimension. LiNi_0.5Mn_1.5O₄ spinel phase began to decompose at around 1000 °C accompanied with structural and morphological degradation. LiNi_0.5Mn_1.5O₄ powders synthesized at 900 °C for 3 h delivered an initial discharge capacity of 139 mAh/g with excellent capacity retention rate more than 99% after 50 cycles.