Electrochemical study of LiMn1.5Ni0.5O4 spinel oxides prepared by two-step process

High-voltage cathode material, LiMn1.5Ni0.5O4, was successfully prepared by two-step process: LiMn1.6Ni0.4O4 particles were obtained by the solid state reaction of oxalate precursors at high temperature such as 900 °C and then the LiMn1.6Ni0.4O4 particles with Li-acetate di-hydrate and Ni-acetate tetra-hydrate were annealed at low temperature. Both spinel phases are ferromagnetic compounds: LiMn1.5Ni0.5O4 has higher Neel temperature (127 K) and larger magnetization (97 emu/g at 4.2 K) than LiMn1.6Ni0.4O4 does (103 K and 79 emu/g). The obtained LiMn1.5Ni0.5O4 particles had low specific surface area, which may reduce the side reaction with the organic electrolyte, and exhibited electrochemical capacity only at high voltage 4.7 V region. In addition, high reversible capacity as well as good cycle performance was attained.